Database management system

EDUPROZ INSTITUTE OF PROFESSIONAL STUDIES


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Unit-1

Data base management system

Introduction Data base is a collection of raw facts and figure users which are arranged f in a proper

manner so than an appropriate record can be maintain. This proper arrangement is known

as DBMS. In each and every CBMS table ae maintained to recorded data. Data is always

represented through relations. There are various kind of relations can be established

between the tables.

A table is a collection of related f information stored so that it is available to many users

for different purpose. The content of data base is obtain by combing data from all the

difference source in an organization so that data available to all the users is redundant.

The data base fundament system is a major software component of data bade system.

Capabilities of data base system 1. Creation of files, addition of data , modification and deletion these are the

important function of data base should perform.

2. Retrieval, collection and deletion of data should be simple.

3. The data should be shorted in form of table and in dense according to the user.

4. Various reports can be provided form system in a standardized way or in a

specific way.

5. Mathematical functions can be performed and can be manipulated easily.

6. There must be data integrity is DB accuracy and consistency.

BASIC CONCEPT OF DBMS

DATA Data is a collection of meaning fact and figure expressed in a form user could

understand it can be resources and processed for further usage.

INFORMATION: Refined data is known as in formation. Any input that foes into

process generate information

PROCESS Any method of reefing data is information data is to information is known as

process.

DATA BASE A collection of related set of data along with necessary details is known as

data base.

DATA BASE BASICS

1. Data item (or domains) the term data item is used for data fields it is the smallest

unit of data. It is also called data elements and elementary item.

Student

Name Age cours



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Lalit 19 BCA

mohit 20 BBA

In the above table values corresponding to the field name is known a data item for

example- lalit, 19, BCA

2. Entity and attribute:

Entity: Any object which can be describe or define is known as entity. Entity are

ways related to the world all such items which have some relevant information to

be strode is known as data base entity entity could be physical and non physical,

tangible or integrity

For eg- student, EMPloyee etc.

Attribute; each entity has a set of particular properties that completely describe it

in context of mini world model. The entity properties are called its attributes

which describe any object for eg an EMPloyee entity may have the attributes like

name EMP_id, address date of birth etc.

3. Logical data and Physical data:

The term logical data or structure refers to the way the programmer see it and

physical sutured refers to the way the data are actually recorded on the storage

media.

4. Schema and sub schema:

Schema it is a logical data base desecration and is down as a chart of types of data

that are used it gives name of entities and attribute and specific the relation ship

between them. The is a frame work in which data values can be fitted for eg

information display system such as that give arrival and departure timing of flight

at airport. The schema will remain same but values are change time to time the

entire format need to be change

FLIGHT

NO

ARRIVAL

TIME

Departure

time

AC001Z 9.00 10.30

AC017T 10.00 11.00

Sub schema the term sub schema refers to the same view but the data item type

and reward type which are used in a particular application or by particular user.

Therefore many different sub schema can be derived from main schema. A simple

analysis distinguished between schema and sun schema may be that if the schema

represented root map of Delhi showing major historical site educational institute

railways station airport etc a subschema could be similar map showing route each

from railway station or form air port.

5. Data dictionary it hold detail information about the different structure and data

type. The different structure and data types the details of logical structure that are

mapped into the differs form details of relationship between data item details o a

all users privileges and access right and performance of recourses wit detail.

PROPERTIES OF DBMS



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1) It should always be certain: A data base about certain part or real world .

this mall part of real world repented in data base in sometimes call mini-

world.

2) Data base should be logical: data base contain persistence data a data

base is a logical coherent collection of which dome inherent meaning once

the data has been accepted by DBMS it can subsequent be remove form

the system only by some explicit request.

3) Data base should have some specific purpose: it is design built and

calculated we data a well define purpose. As intended by group of users

according to their users.

4) Database can be implemented in may available form: it may be

generated and maintained manually or it may be computerized

CHARACTERSITICS OF DBMS

1) Data base system is self describe in nature: data base has a complete definition

or description of data base structure and constraints. It does not depend on any

external information for handling data. It holds information such as strutted of

each file, the time and storage formats of each like and data item and various

constraints on the data.

2) Program data independence: this characteristic allow changing data store

structured and operation without changing the logical structured of DBMS

3) Data abstraction: the form of data I,e actually stored inside the database and

presented to the different user are not the same. A data model is used to hide

storage details and present the user with the conceptual view of database.

4) Multiple view support: it user may see different views of same database

according to the interest of user no matter how the data is stored each user gets

data in his own desire format.

5) Data sharing and multi-user transaction process: a data base may have

multiple users the DBMS must therefore have co-currency control mechanic to

ensure that the result of multi-user access is always correct.

ELEMENT OF DATA BASE MANAGEMENT SYSTEM

1) DDL (Data definition language): DBMS provide a facility known as DDL

which can use to define the concept of schema. It also give some details about

how to implement this schema in physical device used to stored data. This

definition includes all the entity sets and their relation among the entity set. The

definition also including the constraints that have to be maintain including the

constraint on that have to be maintain including the constraints on the values

assign to different attributes in a same or different record. These definition can be

describe meta data about the data in the data base are expressed in DDL of DBMS

and maintain in a complied form the complied form of definition are known as

data dictionary or system catalog.

2) DML(Data manipulation language): DML is a language that access or

manipulated as organized by appropriate data model. Data manipulation includes



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retrieval of data insertion of data deletion or modification of exiting data base.

DML also support query language DML provides command to select and

retrieved data form database command are liked UPDATE, INSERT, DELETE,

etc.

3) DML Pre Compiler: the convert DML statement in an application program to

normal procedural call in the host language the precompiled must interact with

query processor in order to generate the appropriate code.

4) DDL Compiler: the convert’s data definition statement into a set of table these

table contains information related to data based and are in the form that can be

used by other component of database management system.

5) File Manager: it manages the allocation of space on disk storage and the data

structure used to represent information stored in disk the file manager can be

implemented using an interface to the exist file system proved the operating

system to host computer or it can include a file sub system written specially for

DBMS.

6) Data Base manager: it is a program which provides the interface between the

low level data. Stored in data base and the application program and queries

submitted to the system. One of the functions of data base manager is to convert

the user query coming directly through the query processor or indirectly to the

application program.

RESPONSIBILITIES OF DATA BASE MANAGER 1) Interaction with manager: the raw data is stored on the disk using file system

which is unusually provided by a conventional operating system. The data base

manager transaction the various DML statements into low level file system

commands. The Database manager is responsibility for the actual storage retrieval

and updating of data.

2) Integrity enforcement: the data values stored in data base must satisfied certain

types of consistency types of consistency constraints. All the validation and

condition apply to database should be clearly defined.

3) Security enforcement: each and every user of data base need not to have the

access the entire database. It is to have the access the entire database it I the job of

database manager to enforce security requirements.

4) Backup and Recovery: a computer system like any other mechanical device is

subject to failure there are verities of courses of such failure including disk crash.

Power failure software errors. In each of these causes it is the responsibility of

database manager to detect such failure and restored the database as before.

5) Concurrency control: when several user update database concurrently. The

consistency of data may no longer be preserved. It is necessary for the system to

control interaction among the concurrent users are achieving such a control is one

of the responsibility of data base manager.

6) Query Processor: the data base user retrieve data by formulating a query in a

data manipulating language provided by database. The query processor is used to



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interpretation online user query and converts it into an effective series of

operation in base manager for execution. The query processes the structure of

relevant portion of data base and uses this information in modifying a query and

preparing an optimal path to access the database.

7) Data base administrator: the person having total control over the system is

called DBA. The DBA has three level of data base and in consultation with the

overall user community, sets up the definition of global view or conceptual view

of data base it has following responsibility:-

• Schema definition

• Storage structure and access method definition

• Schema and physical organization modification

• Granting of authorization for data access.

• Integrity constraint specification.

DATA BASE USER

1. Data base administration: the user is responsible for creating manipulating and

authorizing access to the database. They are also responsibility for co- ordaining

and monitoring its users. A DBA has complete control on every aspect of data

base. Some time DBA called super user.

2. Data base designer: they are responsible for identifying the data to be stored and

for selecting appropriated structure to represent and store this data.

3. End users: people who’s job require access to database for query updating and

generating report are end users. They carry out their jobs either through

application or by user program.

4. System analyst: System analyses determines the requirement of end users and

develop specifications for transaction.

5. Application programmer: AP implements specification and programs developed

by the analyst so that the specification becomes operational.

6. DBMS system designer and implementation: if somebody has to design and

implement the DBMS module and interface as software package to be

subsequently used.

7. Tool Developers: tool are package of process used are not used very often but are

very important for users at various level



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8. Operators and maintenance personnel: Professional responsibility for actual

execution and maintained of hardware and software are known as operation and

maintenance personnel.

ADVANTAGES OF DBMS

1. Redundancy control: centralized control of data be DBA avoids unnecessary

duplication of data and effectively reduces the total amount of data storage

required Controlling redundancy in data storage and independent and maintained

efforts insure that information is not repeated many times at many places but

stored in single copy which save cost and space and avoiding multiple updating in

case a data item is need to be exchanged.

2. Access control: DBA uses security and authorization around restriction a DBA

has full control on who can use the data in what ways.

3. Persistent for program object and data structure: The object stored in data

base survive the termination of program execution and can later be retrieve the

data remains in the data base even after it has been used many time by users.

4. Multi-user Interface: DBMS provide multi user interface may be implemented

in any of the programming language have compatibility with data base.

5. Complex Relationship Representation: any amount of complexity in the

relationship of given data item can be concisely represented by the database

capability to retrieve and update data easily and effacingly

6. Integrity constraint enforcement: DBMS have capability for defying ad

enforcing constraint that must be satisfied by the data entering by the system and

used by to process

7. Backup and Recovery: A DBMS is a subject to failure due to many reasons

DBMS provide facility for recovering from such software ad hardware failure

8. Data Sharing: since data is stored a single copy many user can use the same

without the need of having separate data for each user. DBMS provide such

facility.

9. Standard Enforcement: A no of international standard may be enforced in the

certain and operation of data base.

10. Flexibility to change data structure: due to data abstraction data structure of

data base can be modified without distrusting the data base users.

11. Reduced application development time: the effort required to develop user

utility reduces considerably and so does the time

12. Availability of update information: the data base always has latest state

providing each user with the up to date information all the time.

DISADVANTAGES OF DBMS

1. Cost: the data base system is a combination of h/w and s/w and training

intensive and calls for a large cost is not justified for a particular situation it is

advisable to look for a cheaper alternative.

2. DBMS are very general in nature if the solution are required for a very

specific purpose it is better to have non- DBMS system.



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3. Overhead on processor: generally a lot of overhead is involved in a DBMS

many of these feature may not be required in a particular situation.

4. In real time system where processing time critical it may not be suitable. The

time overhead may be un acceptable in such case.

THEREE VIEWS OF DATA

DBMS is a collection of interrelated files and sets of program that allow several user to

access and modify files. Major purpose of a data base system is to provide user with an

abstraction view of data

system hide certain details of how the data is stored and maintain since DBMS system are

often used system this is done by defining level be view. There are logical view or

external view or connectional view and internal or physical view.

1. External view: this is the highest level of abstraction as seen by a user this level

of abstraction describe only the part of entire data base.

2. Conceptual view: At his is the next higher level of abstraction which is the sum

total of user view. This level describe what data are actually stored in database in

term of small number of relatively simple structure

3. Internal view: This lowest level of abstraction at which one describe how the

data are physically stored. The interrelationship of three level of abstraction is

given internal view.

The view at each level is describing by a schema as mention earlier is an outline or a plan

that describe the records ands relationship exiting in the view. The schema also describe

in the way in which entity one level of abstraction can be mapped to the next level of

abstraction the overall data base design is called format their exist several schema in the

data base these schema are:-

Portioned into the following level of abstraction

1. At lower level we have physical schema

2. At intermediate level we have conceptual schema

3. At higher level we have several sub schema The general any data base contain one physical schema one conceptual sub schema

several sub schemas.

1. External level or sub-schema: the external level is at the highest level of data

base abstraction are concern to a user or application where any those person of

data base are concern to a user or application programs are concern to a user or

application program are included any number of user may exit for a given global

or conceptual view.

2. Conceptual level schema: at this level of data base abstraction all the data base

entity and the relation ship among them. Them are included in conceptual view. It

describe all the record and relationship including in the concept view ad there fore

in the database there is only one concept schema per data base. This schema also



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contains the method of driving object in the conceptual view from the object in

the internal view.

3. Internal level or physical schema: we find the view at the lowest level of

abstraction it is used in physical storage it indicate how data will be stored and

describe the data structure and access method to be used by data base the internal

view is experience by internal schema which contain the definition of stored

record, the method of representing the data field and access method of

representing the data field and access method to be used.

CHAPTER-2

DATA MODEL

ER MODEL



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Entity relationship model is generalization of old hierarchal and network based approach

it represent the relationship between various entities that is understandable very easily.

Various component of ER-model.

a) Entity: it is a thing or any object physical exquisite. Eg car house and any person

in the real world it may be object with a conceptual existence. Eg: job university

course etc.

b) Attribute: each entity has asset of a particular property that complexly describe

any entity in context of mini world. Each property is called attributes there are

various types of attributes.

• simple: each entity has as single atomic values for the attribute is known

as simple attribute.

Eg- name of any student

• Composite attribute: the attribute may be composed of several

components Eg address of any person include house no, road no, sector

no, city state and pin code.

• Multi value attribute: an entity may have multiple values for the

attribute. Any attribute which can have more than one value for that

attribute is known as multi valued attribute.

Eg- degree attribute of a student can contain BCA, MCA, MBA

c) Entity type and set: an entity type defines a collection of entities that have the

same attributes EMPloyee entity type and company entity type. An entity is an

instance of entity type all entity having the same set of properties are grouped into

an entity type. The collection of all entitles of a particular entity type in a data

base in any point in time is called entity set.

d) Relationship

ADDRESS

STREET CITY STATE PIN CODE

HOUSE NO ROAD NO SECTOR NO



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• Binary relationship: if the association in b/w two entities then it is known

as binary relationship.

• Ternary relationship: it the relationship is b/w three or more entities then

it is known as ternary relationship.

Relationship between entity set

1. One to one: in this relationship one instance of first entity is related to exactly

one instance of second entity.

2. One to many: one instance of first entity is related to one or more instances of

second entity.

3. Many to one: one or more instance of first entity is related to exactly one

instance of second entity.

4. Many to many: many instances of first entity to many instances of second entity.

The overall logical structure of database can be expressed graphically by an ER-Diagram

which is build up by following component

Component Represents

1. Rectangle Entity set

2. Ellipses Entity attribute

3. Diamond Entity relationship

4. Lines link between entity

CHARACTERISITICS OF ER-MODEL Abstraction: it is the simplification mechanism. It is used to hide super flow details of

set of object. It allows one to consternate on the property that are interested in the

application. Example – car is an abstraction of personal vehicle but doesn’t revel details

about model year of manufacturing colors and so on.

There are two main abstraction mechanism used in:-

Generalization: it is an abstraction process of set of object as a single general

characteristics of any specific entity while ignoring the basic details related to it is the

union of no of lower level entities types for the purpose of producing a high level entity

set. Eg: STUDENT is generalization of graduate and undergraduate STUDENT can be

part time or full time.

Specialization: it is an abstraction new characteristic of an existing class of object to

create one or more new classes of object. This involves taking a higher level entry and

using additional characteristics generating by lower level entity. The lower level entity

also inherits the chrematistics of higher level entities specialization may be seen as

reverse process of generalization.

The entity set EMPloyee is a generalization of full time EMP. And part time EMP full

time EMP is again a generalization of faculty and staff where as part time EMP. Is

generalization of teaching and non-teaching EMP. The top down approach in the the

diagram represent specialization and bottom up approach represent generalization.



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Aggregations: it is the process of compiling information on an object and there by

abstracting higher level object.

Example- an entity PERSON is derived by aggregating the charactisicts like name,

address, phone no, another form of aggregation is the abstraction between the object and

relationship. Example: enroll is the relationship between two entitles students and course.

This whole relationship may be viewed as entity

.

HERARICHAL MODEL In the hierarchal database model data is organized in a hierarchal in a ordered tree

structure and the database is a collection of disjoint tree list organization chart. A

hierarchal is a ordered tree and it is a easy to understand. At the root of the tree their have

none. One or more then one child mode. The mode of the tree represent the record type

each tree efficiency representing a root record type. It we define the root record type to be

level zero then the level of its dependent record type can be defined as level-1 . the

dependence of record type at level are set to be level-2 and so on. An occurrence of

hierarchal tree type consist of one occurrence of root record type along with zero or more

accuracy of its dependent sub tree, each type dependent sub tree in true, hierarchal and

consist of record type as its root node, the node having no child means that there is no

dependent node on it is known as leaf node. Hierarchal mode represent a one to many

relationship between two entities whose both the entity have child and parents.

ADVANTAGES 1. Simplicity:in this form data is easy to represent and understand

2. Security:the data base system can enforce various degree of security feat users

3. Database integrity: because of inheritance feature the degree of integrity is high

4. Efficiency:for one to many relationship type of database it is easy to maintain and

manager all the sub entities and children.

DISADVANTAGES 1. Complexity of implementation: the actual implementation of hierarchal database

depends upon the physical storage of data. This makes implementation

complicated.

2. Difficulty in management: the movement of data segments from one location

causes all excising program to be modified making database management a

complex affair.

PERSON

NAME

ADDRESS PHONE NO



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3. Structural dependency: the database has a rigidly defined relationship and hence

any change in any part of the structure of database would access it. This makes

the maintained very difficult.

4. Complexity of programming: programming at his kind of database is relatively

complex because the programmers must know the physical path of data item.

5. Poor probability: the database is not so portable because of their complex

implementation.

NETWORK MODEL

Network model was developing during 1980 by database task group. A network database

consists of collection of records connected to one another through links. A relationship in

this model is known as set. A link is association between process b/w two records. A link

can be viewed as restricted binary form of relationship. The structure of network database

resemble closely with hierarchal. The major difference between the two is that the

hierarchal database each record can have only one parent. But there can be more parent in

the network database model. Therefore the relationship represent the hierarchal database

is one to many but in network database it could be many to many.

NAME STREET CITY A/C

NO

BALANCE

Neha 86-trinagar Delhi 5-56 60000

Amit a-1 Rohini Delhi 5-52 50000

rohit 45-s

Azadpur

Delhi 5-51 40000

ADVANTAGES

1. Simplicity: since most of the database relationship instances are naturally many

to many this database structure is simple to design

2. Better relationship handling: many to many relationship can accommodate most

of the complex relationship existing in actual data relationship scenario

3. Flexibility in data access: data item can be navigated in more than one way

providing much desired flexibility of data access.

4. Standards: Universal standard have been developed and enforce in these types of

database.

DISADVANTAGES

System complexity:

Structural dependency: since access depends upon the navigational path that exist in

database at any time. The programs are not independent of database structure and need to

be modifying whenever database structure is modify.



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RELATIONAL MODEL Relational model was introduced in 1970 by Dr. E. I. Codd. This data model was evolved

using theoretical considerations based on relation calculus by being simple in principle

and the sure can express their queries by using powerful query language. In this model

the relation is the only construct to represent the association among the attributes of any

entity as well as the relationship among the different entity the one of the main reason for

this introducing the model was too increase the productivity of the application program

by eliminating the need of change of application program when change is made to

database users need not to know the exact physical structure to use the database and

protected any change made to these structure they are however still require to know how

the data has been partition into various relation. In this model the user need not to know

the navigational path to data.

Row of the relation are referred as topple and column are referred as attributes each

attribute of a relation has a distinct name the values for a attribute or a column are drawn

form a set of value know as domain. A relationship between the two relation is represent

as ER model by combining primary key of entity involved in the relation and attribute a

correspondence between the two relation is implied by data value of the attribute. In he

relation defined on common domain.

POSITION

EMPLOYEE

EMP NAME DESIGNATION

101 NEHA MANAGER

102 ANJU FACULTY

103 AMIT DIRECTOR

104 PRIYA FACULTY

105 ROHIT MANGER

In this example both EMPloyee and position contain identical name attributes designation

defines on common domain; consequently we join these two relations to form a new

relation position eligibility using common values of attributes designation. Joining the

two or three times taking the value two or there time.

POSITION ELIGIBILTY

EMP_NO POS_NO NAME DESIGNATION

101 301 NEHA MANAGER

PO_ID DESIGNATION

301 MANAGER

302 DIRECTOR

303 FACULTY

304 MANGER

305 FACULTY

306 MANAGER



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102 305 ANJU FACULTY

102 305 ANJU FACULTY

103 302 AMIT DIRECTOR

104 303 PRIYA FACULTY

104 305 PRIYA FACULTY

105 301 ROHIT MANAGER



ADVANTAGES OF RDBMS

1. Structure independence: since there is no need of navigational arrangement for

data access, this database offers complete structural independence. Any change in

the structure of database doesn’t effect DBMS data access mechanism the

program therefore doesn’t need any modification even when the structure is

modify.

2. Simplicity of design and use: relational database providing data independence

and strut aural independence therefore design and implementation is easier then

other type of database.

3. Advance query capability: query in database system is very simple highly

efficient and very powerful tool. It support SQL because both of their foundation

in relational algebra and relation calculus.

DISADVANTGAE System Overhead: Relational database has one disadvantage I,e it increase overhead on

system because it has to handle most of the responsibility of users.

OBJECT ORIENTED DATA MODEL With the popularity of object oriented technology the need for object oriented database

arise when database capability are integrated with OOP’s language it is known as object

DBMS an ODBMS makes database object appears as programming language object in

one or more oops language with the feature of DBMS like concurrency control, data

recovery and advance query capability. Some of the example of object oriented language

is:-

C++, C#, JAVA ODBMS provides low cost development and bets performance

combination when using the object oriented language because they stored object on disk



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and have transparent program integration with OOP’s. this is because ODBMS store

exactly the same object code I, e used by application program.

ADVANTAGES

There are two benefits of using objects oriented data model. The benefits I that when we

used object based model we have to write less code than if we were writing to DBMS.

The reason for less amount of code is that program written I n java or C++ need not to

translate in any other code.

The second benefits is related to production if we are working in complete and complex

data on ODBMS give better performance which is thousand times faster than RDBMS

because when the data is read off the disk is already in a format I,e used by java or C++

so on translation is required.

OBJECT RELATIONAL DATA MODEL

This model support object oriented and relational concept in this model it is possible to

provide well define interface for the application it facilitates the reusability of data object

a structure once created can be sense which is the fundamental property of object oriented

data model. Oracle is the best example of this kind of model.

ADVANTAGES

1. Simplicity of design: Because of object oriented this approach is orientation

approach is simple to design

2. Data base integrity: it is assured to the maximum level because of inheriting

saving of object.

3. Symantec content handling: object orientation of data in object oriented

database carriers proper meaning of each and every object.

4. Structure to data independence: object relational database provide structure and

data independence.

DISADVANTAGES

1. Increase system overhead:

2. Lack of standards: object oriented data model does not therefore object

relational database uses specific standard.



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CHAPTER-3

Relational data manipulation

INTRODUCTION

This model was introduce be TODCORK ins 1970 that user the concept of mathematical

hence the database is considered as a collection of relations. A relation is a table where

each row represent a set of data values. A row in the table called tupple and columns are

attributes. A relational schema (R) is denoted as R(A1,A2,A3….Ai)

Where R is denoted as R(A1,A2,A3….) where R is relation name and A stands for

attributes. The degree of relation depends upon the number of attributes used in a

relation. For e g. In a relational schema students (roll no, name, course) there are 3

attributes so the degree of relation will be three.

CHARACTERSTIC OF RELATION

1. A tupple can be considered as set of attributes and value.

For e.g. t1(<Roll No, 101>,<Name, Amit>,<Course, BCA>)

2. Tupple odering is not a part of relation

for e.g. t1(<name, Amit>,<Roll No,101>,<Course, BCA>)

RELATIONAL MODEL NOTATION



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1. A relational schema R1 is denoted as R(A1,A2,…….Ai)

2. A tupple in a relation is denoted as t1=(V1,V2,………Vi)

3. The letter Q,R,S denotes relation name.

4. The letter t,u,v denotes tupple.

5. An attributes A can be qualified with the relation name R using the denotes tupple

For e.g. student, Roll no, Student, Name

1) DOMAIN CONSTRAINTS The set of all the values that an attribute can accept is known as domain of attributes.

The domain constraint specify that the value of each attributes Ai must be atomic

domain or dom(Ai) atomic domain are general set such as set of integers real no

character string and so on. Domain on any attribute restrict the attribute from taking

the value other then the set of domain domain constraints for e.g an attributes name

can have data type string or its length could be 10 character long. Another constraint

that applied on any attributes is NULL constraint. The absence of particular attribute

values in a tupple is expressed by NULL, present the value is not attributes. But if not

null constraint is applied on attribute then it cant accept NULL values i,e there must

be any value in all tupple of that attributes.

2) ENTITY INTEGRITY CONSTRAINT It implies that if an attribute A of a relation R is a primary attribute then A can’t

accept NULL value this constraint is applied on primary key and restrict it from

having NULL value become if any instance of primary key are permitted to have

NULL then the key cant be used as a unique key.

ID Name

101 Amita

@ Anjali

104 Ajay

107 Anirudh

110 Arjun

3) REFERENTIAL INTEGRITY CONSTRAINTS

Referential integrity constraint status that two relations referred to each other then a

relation having a foreign key which is a primary key of another relation must have a

value which is from set of value from table in which it is a primary key or it may be null.

This rule is concerned with the foreign key that is with the attribute of a relation having

domain that are those of primary key of another relation. Suppose these are two relations

S and R. R refers to the relation and S to the set of attribute that form a primary key of a

ID Name

101 Rohit

102 Ankit

103 Anshul

104 Amita



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relation S. This set of attribute R is known as foreign key in a tupples the value of foreign

key in tupples in R must either be equal to the value of primary key of S or it could be

NULL.

EMPLOYEE

EMP_CODE NAME MGR_ID

E101 Amit M101

E102 Anjali M101

E103 Anju M102

E104 arjun @

MANAGER

Mgr_ID Name

M101 Kiran

M102 Rohit

M103 Rohan

M104 Ritu

M105 Karan

Here relation EMPloyee refers to the relation manager through mgr_id which is the

primary key of manager. So manager Id is a foreign key of EMPloyee relation.

SET ORIENTED OPERTAION

Set Operator Description Pseudo Examples

SELECT Returns all rows in a table that

match a certain criteria

SELECT from A where C2 is equal to 1 = R-5

PROJECT Returns all values for selected

attributes, showing a vertical

view of a table.

PROJECT C1 for table A = R-6

JOIN Combines two or more tables,

using natural, equi, theta, left

outer or right outer joins.

A JOIN E ON C1 and C3 (natural) = R-7

A JOIN E (left outer) = R-8



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A JOIN E (right outer) = R-9

UNION Combines all rows in one table

with all rows in another table,

without including duplicates.

A UNION B = R-1

INTERSECT Compares two tables and

combines only the rows that

appear in both tables

A INTERSECT B = R-2

DIFFERENCE

Compares to tables and

returns all rows that are found

in the one, but not the other

table.

A DIFFERENCE B = R-3

PRODUCT

Create all possible pairs of

rows from two tables,

resulting in the Cartesian

Product

A PRODUCT E = R-10

DIVIDE

Weird operator, where the

one table has two columns

and the other table one

column. Returns value of

Column 2, which is associated

with every value of Column 1

in both Table 1 and 2. Weird ...

C DIVIDE D = R-4

SET OPERATIONS

There are two groups of operations:

• Mathematical set theory based relations:

UNION, INTERSECTION, DIFFERENCE, and CARTESIAN PRODUCT.

• Special database operations:

SELECT (not the same as SQL SELECT), PROJECT, and JOIN.



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• SELECT

SELECT is used to obtain a subset of the tupples of a relation that satisfy a

select condition.

For example, find all EMPloyees born after 1st Jan 1950:

SELECT dob '01/JAN/1950'(EMPloyee)

• PROJECT

The PROJECT operation is used to select a subset of the attributes of a relation by

specifying the names of the required attributes.

For example, to get a list of all EMPloyees surnames and EMPloyee numbers:

PROJECTsurname,EMPno(EMPloyee)

• SELECT and PROJECT

SELECT and PROJECT can be combined together. For example, to get a list of

EMPloyee numbers for EMPloyees in department number 1:

Figure : Mapping select and project

Examples:-

Consider two relations R and S.

• UNION of R and S

The union of two relations is a relation that includes all the tupples that are either

in R or in S or in both R and S. Duplicate tupples are eliminated.

• INTERSECTION of R and S The intersection of R and S is a relation that includes all tupples that are both in R

and S.

• DIFFERENCE of R and S

The difference of R and S is the relation that contains all the tupples that are in R

but that are not in S.



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SET OPERATIONS - REQUIREMENTS

For set operations to function correctly the relations R and S must be union compatible.

Two relations are union compatible if

• They have the same number of attributes

• The domain of each attribute in column order is the same in both R and S.

UNION Example

Figure : UNION

INTERSECTION Example



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Figure : Intersection

DIFFERENCE Example

Figure : DIFFERENCE

CARTESIAN PRODUCT

The Cartesian product is also an operator which works on two sets. It is sometimes called

the CROSS PRODUCT or CROSS JOIN.



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It combines the tupples of one relation with all the tupples of the other relation.

CARTESIAN PRODUCT example

Figure : CARTESIAN PRODUCT

JOIN Operator

JOIN is used to combine related tupples from two relations:

• In its simplest form the JOIN operator is just the cross product of the two

relations.

• As the join becomes more complex, tupples are removed within the cross product

to make the result of the join more meaningful.

• JOIN allows you to evaluate a join condition between the attributes of the

relations on which the join is undertaken.

The notation used is

R JOINjoin condition S

JOIN Example

Figure : JOIN



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NATURAL JOIN

Invariably the JOIN involves an equality test, and thus is often described as an equi-join.

Such joins result in two attributes in the resulting relation having exactly the same value.

A `natural join' will remove the duplicate attribute(s).

• In most systems a natural join will require that the attributes have the same name

to identify the attribute(s) to be used in the join. This may require a renaming

mechanism.

• If you do use natural joins make sure that the relations do not have two attributes

with the same name by accident.

OUTER JOIN

Notice that much of the data is lost when applying a join to two relations. In some cases

this lost data might hold useful information. An outer join retains the information that

would have been lost from the tables, replacing missing data with nulls.

There are three forms of the outer join, depending on which data is to be kept.

• LEFT OUTER JOIN - keep data from the left-hand table

• RIGHT OUTER JOIN - keep data from the right-hand table

• FULL OUTER JOIN - keep data from both tables

OUTER JOIN example 1

Figure : OUTER JOIN (left/right)

OUTER JOIN example 2



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DIFFRENCE OF DBMS AND RDBMS

DBMS:

1)In DBMS no relationship concept

2)It supports Single User only

3)It treats Data as Files internally

4)It supports 3 rules of E.F.CODD out off 12 rules

5)It requires low Software and Hardware Requirements.

6)FoxPro, IMS are Examples

RDBMS:

1)It is used to establish the relationship concept between two database objects, i.e,

tables

2)It supports multiple users

3)It treats data as Tables internally

4)It supports minimum 6 rules of E.F.CODD

5)It requires High software and hardware requirements.

6)SQL-Server, Oracle are examples



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CHAPTER-4

Relational database design

HOW TO DESIGN A DATABASE

PURPOSE The problem with data is that it changes. Not just its individual items' values change, but

their structure and use, especially when kept over extended periods of time. Even for

public records that may have been kept for hundreds of years, there are occasionally

changes in what data elements are captured and recorded and how.

Therefore, a method to avoid problems due to duplication of data values and modification

of structure and content has been developed. This method is called normalization.

You normalize a database in order to ensure data consistency and stability, to minimize

data redundancy, and to ensure consistent updatability and maintainability of the data,

and avoid update and delete anomalies that result in ambiguous data or inconsistent

results.

SOME KEY CONCEPTS

Before we continue, I would like to show the correlation between the formal names of

Tables, Rows, and Columns in Relational Theory and their more common counterparts:

Formal Name Common Name Also Known As

Relation Table Entity



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Tuple Row Record

Attribute Column Field

A PRIMARY KEY is one or more columns whose values uniquely identify a row in a

table (See rule #2 above).

A CANDIDATE KEY is one or more columns whose values could be used to uniquely

identify a row in a table. The Primary Key is chosen among a table's Candidate Keys.

RELATIONAL DATABASE DESIGN

The process of obtaining a set of relation along with respective control if any is known

as database design although tables will suffer from a no of difficult when database

operation are perform on them subsequently this indicates bad database design. A good

database design doesn’t have such problem clearly different designer would arrive at

different design one being better then other in some aspects exactly what makes a

database design good is that it offers both space efficient and process efficiency. Could

be taken as reasonably good designer in other word database should occupies minimum

storage space and yet eliminate the following problem.

1. Redundancy

2. Inconsistency

3. Insertion Anomalies

4. Deletion

5. Modification

6. Functional Dependency

7. Un-Normalization

NORMALISATION

Normalization is the formalization of the design process of making a database compliant

with the concept of a Normal Form. It addresses various ways in which we may look for

repeating data values in a table. There are several levels of the Normal Form, and each

level requires that the previous level be satisfied.

The normalization process is based on collecting an exhaustive list of all data items to be

maintained in the database and starting the design with a few "superset" tables.

Theoretically, it may be possible, although not very practical, to start by placing all the

attributes in a single table. For best results, start with a reasonable breakdown

Normalization the goal of relation database to generate a set of relation that allows

storage of information without unnecessary redundancy yet permits to retrieve

information easily the right approach is to design the schema as that are in appropriate

normal form some of the process of removing functional dependency from a relation is

know as normalization. It is processes of organizing the data in database in such a way so

as to protect all the rules or guide line of database design and to eliminate the problem

like data redundancy and operating anomalies it is basically a process of decomposability

method in which a relation having under desirable dependency is split into two or more



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relation and their by removing the undesirable effect of existing dependency relation are

to be attendant during the life time of database we don’t lose any information or don’t

introduce any inconsistency the type of attention normally needed are:-

1. Insertion of new data value to a relation these should be possible without being

force to leave blank field for some attribute.

2. Deletion of tupples should be possible without loosing any vital information.

3. Updating a value of an attribute in a tupple this should be possible without

extensive searching of all the tupple in the relation.

FIRST NORMAL FORM If the value of a relation instance is atomic for every attribute in a relation then

relation is said to be in first normal form. The attribute item line is not a single

attribute but it is composed of many attribute besides this is the number of item line is

variable this form is not suitable for storage as a file in a computer further retrieval of

data is difficult to fine out how many item with a specified item code are ordered one

must breakup the composite attribute first before attEMPting a search that way this

relation is said to be un normalized to normalized this relation a composite attribute is

converted into individual attribute after doing this common value for a composite

attribute are duplication as many time as there are line in composite attribute.

ORDER NO ORDER

DATE

ITEM

CODE

QUNTITY PRICE/UNIT

101 020199 111 52 50

101 020199 333 30 60

101 020199 222 20 17

102 040299 444 45 20

102 040299 333 30 60

103 120499 333 40 60

The above form this form is also called that file as there are no composite attribute

and every attribute single and describe one property.

Functional dependency: ORDER NO� Order Date

ITEM CODE�Price

ORDER NO �Item code�Quantity

SECOND NORMAL FORM

A relation is said to be in second normal form if it is in first normal form non-key

attribute is functionally dependent on key attribute if the key has more then one

attribute then no non-key attribute. The above example is in first normal form in

which key is order no. and item code. The following dependency is existing in the

table.

ORDER NO�� Order Date



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ITEM CODE��Price

ORDER NO ��Item code��Quantity

Here a non-key attribute quantity is dependent on order no and item code but order

date which is a non-key attribute is dependent on order no which is a part similarity

price is also dependent on item code. Which is again a part of key? Those two non-

key attribute are dependent only on part of key. Those two of key but not on whole.

This relation is not in second normal form it can be transaction to second normal form

by splitting it into there.

ITEM ORDER

ORDER

NO

ORDER

DATE

101 020199

102 040299

103 120499

ORDER

NO

ITEM

CODE

QUNTITY

101 111 52

101 333 30

101 222 20

102 444 45

102 333 30

103 333 40

After transforming the relation form first normal form to second normal form repetitive

data like order date has been remove further if an order for an item is cancelled the price

of an item is not lost.. for example if the order no 102 for the item code 444 is removed in

first normal form table then the forth row will be remove and the price of item is lost but

after converting it in second normal form this with not be a problem.

THIRD NORMAL FORM

A relation is said to be in third normal form if it is in 2nd

normal and non-key attribute of

a relation is functionally dependent on any other no-key attribute.

ITEM

CODE

PRICE/

UNIT

111 50

222 17

333 60

444 20

ROLL NO NAME DEPARTMENT YEAR HOSTEL

101 Neha Physical Edu 1 Ganga

102 Priya Chemistry 1 Ganga

103 Lalit Maths 2 Krishna



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Here roll no is the key and all the other attribute re functionally dependency on it this

table is in second normal form in which it known that in the. Collage the first year

students are accommodated in Krishna and year student in Krishna and third year in

Kaveri and year in Godawari them non-key attribute hostel name is department on key

attribute year.

The dependency of hostel name on year Leeds to duplication of data. If it is decided to

ask all the first year student to move to Kaveri hostel all the second year student to move

to Ganga hostel this change should be made at many place also if the student roll no 106

left the collage the information regarding Godawari hostel is deleted so this table is not in

third to transform third we will introduce another relation which include the functionality

related to non-key attribute.

ROLL

NO

NAME DEPARTMENT YEAR

101 Neha Physical edu 1

102 Priya Chemesrty 1

103 Lalit Maths 2

104 Nitin Botany 2

105 Mohit Geology 3

106 Kunal Zoology 4

YEAR HOSTEL

1 Ganga

2 Krishna

3 Kaveri

4 Godawari

104 Nitin Bootany 2 Krishna

105 Mohit Geology 3 Kaveri

106 Kunal Zoology 4 Godawari

ROLL NO

NAME

DEPT

YEAR

HOSTEL



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BOYCE CODD NORMAL FORM

Reduce third normal form entities to Boyce/Codd normal form (BCNF) by ensuring

that they are in third normal form for any feasible choice of candidate key as primary

key.

In short, Boyce Codd normal form (BCNF) addresses dependencies between columns

that are part of a Candidate Key. Some of the normalizations performed above may

depend on our choice of the Primary Key. BCNF addresses those cases where applying

the normalization rules to a Candidate Key other than the one chosen as the Primary Key

would give a different result. In actuality, if we substitute any Candidate Key for Primary

Key in 2NF and 3NF, 3NF would be equivalent with BCNF. In a way, the BCNF is only

necessary because the formal definitions center around the Primary Key rather than an

entity item abstraction. If we define an entity item as an object or information instance

that correlates to a row, and consider the normalization rules to refer to entity items, this

normal form would not be required.

EXAMPLE:-Consider a scenario of a large development organization, where the

projects are organized in project groups, each with a team leader acting as a liaison

between the overall project and a group of developers in a matrix organization. Assume

we have the following situation:

• Each Project can have many Developers.

• Each Developer can have many Projects.

• For a given Project, each Developer only works for one Lead Developer.

• Each Lead Developer only works on one Project.

• A given Project can have many Lead Developers.

In this case, we could theoretically design a table in two different ways:

ProjectNo Developer Lead Developer

20020123 John Doe Elmer Fudd

20020123 Jane Doe Sylvester

20020123 Jimbo Elmer Fudd

20020124 John Doe Ms. Depesto

Case 1: Project Number and Developer as a Candidate Key can be used to determine the

Lead Developer. In this case, the Lead Developer depends on both attributes of the key,

and the table is 3NF if we consider that our Primary Key.



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Lead Developer Developer ProjectNo

Elmer Fudd John Doe 20020123

Sylvester Jane Doe 20020123

Elmer Fudd Jimbo 20020123

Ms. Depesto John Doe 20020124

Case 2: Lead Developer and Developer is another Candidate Key, but in this case, the

Project Number is determined by the Lead Developer alone. Thus it would not be 3NF if

we consider that our Primary Key.

In reality, these three data items contain more than one relation (Project - Lead Developer

and Lead Developer - Developer). To normalize to BCNF, we would remove the second

relation and represent it in a second table. (This also illustrates why a table is formally

named a relation.)

FOURTH NORMAL FORM

Reduce Boyce/Codd normal form entities to fourth normal form (4NF) by removing

any independently multivalued components of the primary key to two new parent

entities. Retain the original (now child) entity only if it contains other, nonkey

attributes.

Where BCNF deals with dependents of dependents, 4NF deals with multiple,

independent dependents of the Primary Key. This is a bit easier to illustrate. Let us say

we wanted to represent the following data: Manager, Manager Awards, and Direct

Reports. Here, a Manager could have multiple Awards, as well as multiple Direct

Reports. 4NF requires that these be split into two separate tables, one for Manager -

Awards, and one for Manager - Direct Reports. We may need to maintain a Managers

table for other Manager attributes.

This table:

Lead Developer Developer

Elmer Fudd John Doe

Elmer Fudd Jimbo

Sylvester Jane Doe

Ms. Depesto John Doe

ProjectNo Lead Developer

20020123 Elmer Fudd

20020123 Sylvester

20020123 Elmer Fudd

20020124 Ms. Depesto



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Manager Awards Direct Reports

Scrooge McDuck Stingy John Donald Duck

Minnie Mouse Mouse of the Month Mickey Mouse

Minnie Mouse Mouse of the Year Pluto

Clara Goofy

becomes two tables:

Manager Awards Table

Manager Awards

Scrooge McDuck Stingy John

Minnie Mouse Mouse of the Month

Minnie Mouse Mouse of the Year

Clara

Direct Reports Table

Manager Direct Reports

Scrooge McDuck Donald Duck

Minnie Mouse Mickey Mouse

Minnie Mouse Pluto

Clara Goofy

FIFTH NORMAL FORM

Reduce fourth normal form entities to fifth normal form (5NF) by removing pair wise

cyclic dependencies (appearing within composite primary keys with three or more

component attributes) to three or more parent entities.

This addresses problems that arise from representing associations between multiple

entities with interdependencies. Making it 5NF consists of adding parent tables, one for

each meaningful combination that has children in the original table.

A table with such information is 5NF if the information cannot be represented in multiple

smaller entities alone.

An example of such a situation may be the representation of Actors, Plays, and Theaters.

In order to know who plays what and where, we need the combination of these three

attributes. However, they each relate to each other cyclically. So to resolve this, we



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would need to establish parent tables with Actor - Play, Play - Theater, and Theater -

Actor. These would each contain a portion of the Primary Key in the Actor, Play, and

Theater table.

Actor Play Theater

Billy Bob Catcher in the Rye West 42nd

Ann Catcher in the Rye West 42nd

John Catch-22 Broadway

Lily Hamlet Broadway

Lisa Cats West 42nd

Andy Cats Darlington

FUNCTIONAL DEPENDENCIES NOW are going to discuss functional Dependencies.

For our discussion on functional dependencies assume that a relational schema has attributes

(A, B, C... Z) and that the whole database is described by a single universal relation called R

= (A, B, C, ..., Z). This assumption means that every attribute in the database has a unique

name.

What is functional dependency in a relation?

A functional dependency is a property of the semantics of the attributes in a relation.

The semantics indicate how attributes relate to one another, and specify the functional

dependencies between attributes. When a functional dependency is present, the

dependency is specified as a constraint between the attributes.

Consider a relation with attributes A and B, where attribute B is functionally dependent

on attribute A. If we know the value of A and we examine the relation that holds this

dependency, we will find only one value of B in all of the tupples that have a given value



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of A, at any moment in time. Note however, that for a given value of B there may be

several different values of A.

In the figure above, A is the determinant of B and B is the consequent of A. The

determinant of a functional dependency is the attribute or group of attributes on the left-

hand side of the arrow in the functional dependency. The consequent of a functional

dependency is the attribute or group of attributes on the right-hand side of the arrow.

CHAPTER-5

STRUCTURE QUERY LANGUAGE

SQL stands for structured query language and it is also pronounce as SEQUEL. It is the

most popular database query language support SQL. SQL is set of command that

program and user may use to access data within the database tools are used to access



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database without directly using SQL. However theses application also translates the

action into SQL FORMAT.

ADVANTAGE OF SQL

1. NON PROCEDURAL LANGUAGE: It is a non procedural language in that the

user do not have to specify how the SQL Commands work like macros that have

already being written for the user. A non-procedural language is free from writing

algorithm a single command can do the job.

2. UNIFIED LANGUAGE: SQL commands for variety of task which includes the

following.

• Inserting, updating and deleting rows in the table.

• Creating, replacing, altering and dropping objects

• Controlling access to the database and its objects.

• Generating database consistency

• Query data.

3. COMMON LANGUAGE FOR ALL RDBMS: Because all major relational

database system support SQL one can transfer all skills one have gain with SQL

from one database to another since all the programs written in SQL are portable

they can often be moved from one database to another with very little

modification.

4. EMBEDDED SQL : It refers to the use SQL commands embedded with

procedural Programming language embedded SQL is collation of these

commands. RDBMS also provided pre-complier that support embedded SQL

statement that can be understanding by procedural language compiler some of the

pre-compiler are some of the precompiled are as follows

• ADA pre-compiler

• C/C++ pre-compiler

• COBOL pre complier

• FORTAN

• PASCAL

• PL/1 5. DATABASE OBJECT: RDBMS two types of database object.

• Schema object: Schema object is a collection of logical structure of data A

schema is owned by database user and has the some name as that object can

be create and manipulated with SQL and included the following types of

object: cluster, index snapshot procedural view like logs synonymous triggers

functions table.

• Non-schema object: Other types of object are also stored n the database and

can be created and manipulated with SQL but are not containing in a schema.

Profile rollback segments user, roles, table space.

OBJECT NAMING CONVENTIONS:



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1. Name must be from 1 to 30 characters long.

2. Name of database are limited to 8 characters but name of database link can be

long as no character.

3. Naming can’t be contained quotation mark.

4. Name is not case sensitive.

5. A name must begin with a alphabet character.

6. Name can also contain alphanumeric character from the database character set

and the character like fewer than score is not permitted.

7. Name of the database link can also contain dot(.), &.

8. Columns in the same table or view can’t have same name.

OBJECT NAME GUIDELINES 1. Use full, descriptive, pronounceable name or well known abbreviations.

2. Use consistence naming rules.

3. Use the same name to describe the same entity or attribute across the table.

4. Name must be short and self explanatory.

5. Using consistence naming rule help the user to understand each part of table.

VIEW AND INDEXES

VIEW

A view is a customized presentation of data form one or more table view derived through

data from the table on which thy are based it is known as based table all operation

perform on a view actually affect the base table of the view can be use for following

reasons

1. It provides an additional level of table security by restricting access to the

predefined table. For e.g. you can create a view of table that does not include

sensitive data link salary, acc_no, and ID.

2. It hide data complexity database usually include many table and by creating a

view combine information form one or more table can be generated. You can

generate a view i.e. a combination of EMPloyee table a department table.

3. To present the data in difference perception from that the base table view provides

a means to rename the column without affecting the base table for e.g. to store a

complex query a query might perform exclusive calculation with the table

information by sharing this query as a view the calculation are perform only when

the view is query.

INDEXES

An index is used to quickly retrieve information from a database project. Indexes help

you to retrieve specific information faster and it also provide the fast access to the

database. Indexing create an ordering of file consisting of list of record in a logical record

order along with the corresponding physical location in the table indexes are created in

one or more columns of table once creating an index is automatically maintain by data

base system.

SQL COMMAND, SYNTAXES AND USAGE:

SQL command can be categorized the following category:-

1. Data definition language command.

2. Data manipulation language command.

3. Transaction control command.



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DATA DEFINITION LANGUAGE: There command allow user to create and

modify various database object. It includes the following tasks:

1. Create objects

2. Delete or drop objects

3. Ground and revoke privilege.

4. Analyses information on table or index.

5. Establish auditing options.

1. CREATE COMMAND: This command is used to create commands to

create a table. The create statements specify the name of table columns

create command is used to create indexes and views.

Syntax:

Create table<table name> (<attribute list>);

E.g.: Create table EMP (EMP_no integer, not_null, name

varchar(10), salary integer, job_description varchar(25))

2. ALTER COMMAND: The definition of existing relation can be altered

by using the Alter statement. This statement allows a new column to be

added in an existing column from the relation and existing column from

the relation and all the values from existing tupple will be deleted.

Relation. The existing tupple of altered relation. Are logically considered

to be assign a null value to the added column alter command is used to

delete an existing column from the relation and all the values from

existing tupple will be delete.

• To add a column

Alter table <table name>

Add (column name data type)

E. g alter table EMP add (dept no integer)

• To delete a column:

Alter table<table name>

Delete (column name data type);

E.g. alter table EMP delete (salary integer)

3. DROP COMMAND: This command is used to delete an existing relation

from database.

Syntax:

Drop table <table name>

E. g drop table EMP; 4. Grant command: This command is used to system privileges to user and

groups.

5. Revoke: This command is used to take system privileges from users and

group.

(B) DATA MANIPULATION LANGUAGE COMMAND:



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DML command query and manipulation data in existing schema object these

command implicitly comment the current transaction. These commands are listed

as follow:

1. INSERT: this is used to insert a new tupple into a specified relation the

value for each field o the record is given through this command.

Syntax:

Insert into <table name> values (<value list>);

E.g.: insert into EMP values (101,’Priya’, 10000,’Programmer’);

2. SELECT: this command is used for data retrieval. It is the only retrieval

command in SQL that specify the method of selecting the tupple which is

selected from the specifies relation by using form keyword and the

selecting is done by using where clause this command perform both

selection and projection.

Syntax:

Select [distinct] <target list>

Form<table name> where <predicate>; The distinct option is used in select command to eliminate duplicate tupple in the

result without this option duplicate tupple may appear in the result.

The target is the method of specifying a projection operation of resultant relation

The form clause specify the relation to be used in evaluation of the statement the

where clause is used to specify the predicate (condition) involving the attributes

of relation appearing in the form clause.

Example:

• Select* form EMP; It will select all the tupple and all the attribute from Employee table.

• Select distinct name from EMP;

It will show all values of name attribute without repeating any value.

• Select EMP_no, Name from EMP

where salary>10000;

• Select EMP_no name form EMP

Order by name dec;

3. UPDATE: this command is used to modify one or more record in a

specified relation. This record to be modified are specified by a predicate

in a where clause of a new value of the column to be modified is specified

be set clauses.

Syntax:

Update<table name>

Set<target value list> where <predicate>;

e.g update EMP set salary=15000 where EMP_no<107;

4. DELETE: this command is used to delete one or more record from the

relation the record to be delete are specified by the predicate in where

clauses.



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Syntax:

Delete table <table name>

Where<predicate>

e.g delete EMP where salary<1000;

5. ARITHMETIC AND AGGREGATION OPERATION: SQL provide a

full compliment of arithmetic operators and functions. This include

functions to fine avg minimum maximum sum and to count the total

numbers of occurrences.

1) To get average

Select avg<attribute name> from<table name>;

E.g. select avg (price)

From Product;

2) To get maximum and minimum

Select max <attribute name>, mini<attribute name>

from<table name>;

E.g. select max(price), min(price)

from Product;

3) To count number of occurrence select count <attribute name>

from<table name>

E.g select count(distinct name)

From EMP;

4) To find sum

Select sum<attribute>

From<table name>

Select sum(salary)

From EMP;

(C)TRANSACTION CONTROL COMMAND

These commands are used to manage changed made by data

manipulation language commands.

1) COMMIT: It is used to make permanent the changed made by

statement issued at the beginning of transaction.

2) ROLLBACK: It is used to undo all changes since the beginning of

transaction or since a save point.

3) SAVE POINT: It is used to establish a point back to which you may

roll.

4) SET TRANSACTION: It is used to establish properties for the

current transaction.

ARITHMETIC EXPRESSION: An expression is combination of one or more

values operation and function which evaluate to a value. There are following

arithmetic expression used in SQL add, sub multiple, divide. If your arithmetic

expression contain more than one operation the priority is give to *, /, +,-.

e.g. select EMP_name , sal+250*12 from EMP;



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SQL OPERATORS

1) BETWEEN OPERATOR: It test for value between and inclusive of low

and high range for e.g. We want to see those Employee whose salary b/w

1000 to 2000 we need to perform following query.

Select name salary from EMP.

Where salary b/w 1000 and 2000.

2) IN OPERATOR: It test for value in specified list for e.g to find out all

Employee who have one of the three ID nos. 7902,7566,7788

Syntax

Select<attribute list>

Form<table name> where attribute in(V1,V2,V3….Vn);

e.g select name, salary, ID, from EMP

where ID(7902,7566,7788);

3) LIKE OPERATOR: Sometimes you may not know the exist value to be

searched using the like operator it is possible to select a row that match a

character pattern. Select* from EMP

Where name like ’S%’;

4) IS NULL: This operator specify test for value that are null. For e.g to find

all Employee who have no commission the following query will be given.

Syntax:

Select*from<table name>

Where commission is NULL; is not null

CHAPTER-6

MS-ACCESS

Q1. What is MS Access is?



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Ans: MS-Access is Microsoft database management system is a part of Microsoft office

suite. It is very easy to use because of User-friendly interface mechanism it present

almost all the features and characteristics of relational database management system with

the help of MS-Access.

1. We can create database in a tabular format (RDBMS).

2. Two or more then two table can be joined to enhance or to represent RDBMS

capability.

3. We can create query using MS-Access.

4. We can generate reports on the created database.

5. We can add recorded to new table by using forms on the table.

6. Records from the table can be restricted, manipulated inserted or deleted very

easily.

We don’t need any detailed study to learn and use MS-Access if we have knowledge

about DBMS. We can easily use MS-Access for database creation another advantage of

ms-access is that is compatible with most of the front end programming tools like VB

that is we can create front end part of the s/w using VB and is database can be created

using MS-Access whatever, we add or delete in the forms at front end part it will

automatically updated in the table in the table of DBMS in ms-access. Thus using ms-

access, you can develop a fully functional database application.

We can use MS-Access in the following typical situation:

1. To create telephone directory of contact.

2. To create record of Employee of our organization.

3. To create MIS for our organization etc.

Thus whenever a range volume of data needs to be stored, maintained manipulated and

utilized in various decision- making activates, we can use MS-Access.

Ques2. How would you design database in MS-Access?

Ans: steps:

1. Click at file->new

OR

Click at two new two button on the toolbar

OR

Press Ctrl+N

2. In the task pane, click at Blank database.

3. After that access asks you to close a name and location to save the database enter

the name and relation in the file new database dialogues box and then press ok.

4. Accesses create a blank database and a database window appeared on the screen

having two main parts.

a) Database object tab

b) Database definition commands part.

5. Click on table in object tab it will show three options known database definition

command.

a) Create table in design view.



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b) Create table by using wizard.

c) Create table by entering.

6. Design view

a) Click on create table in design view.

b) Then a window for designing:

Table will appears. Enter field names in field name set their data type and

mention their respective meaning. In the lower part of the window, there

are various option through which you can put constraints on datable fields

also set on field as primary key by right clicking on it and then select

primary key option.

c) After finishing the structure definition click at the close button of the

table window. Then access ask ”Do you want to save the change to the

design of the table if pres yes button then a dialogue appears that ask

then name of the table enter the appropriate name and press ok

button.”

(B) Wizard

1. Click on “create table by using wizard”.

2. Then a dialogue box named table wizard appeared on the screen

• Select table type-business or personal.

• Select table name from same table.

• Select sample field one by one and press button.

• If you want to rename the fields then select the field and press rename

field button and then give it a new name. Finally press next button to

move ahead.

Then the dialog box access the name for your table gives an appropriate name. it also ask

for the setting the primary key if you select-

Yes set a primary key for me. Then system set a primary key for your table and if you

select click to finish.

DESIGN VIEW

Click on create table in design view

Then a window for designing

Table will appear in feature field comes in field name set their data type and match their

respective meaning in the lower part of the window there are various option through

which you can put constraint on data type also put constraint on data type

Ques3: Who do you mean by Queries in MS-Access? Explain types how query

quires created using a wizard how would you create multi table query in access?

Ans: The primary accurate inform in a proper format the efficiency of a database is

determined by the speed with which it retrieve data and present it in a user

defined format the process of accessing the database and retrieving data

selectively is known as querying.

A query is a database objective that create a datasheet of specified field and

record form one or more table. A query display the answer to a question about the



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data in our data base although table store all data though which we can vie any

required data but with the help o query we can have data in the format specified

by us and also it provide the facility to view data on the specified criteria queries

behaves and appear just like a table but one important difference between a table

and a query is record while a query is stored with only selected recorded and this

selection with is based on some criteria also a query on have record form more

than one table.

Type of queries:- Access provide many different type of queries they can be

grouped into six basic categories.

1. Select query: it is used to extract only specified and selected fields form one or

more table.

2. Parameter Query: it is used to extract data form the table on the basis of

specified criteria can be more than one.

3. Cross tab query; it is used to display summarized valued sum, count, avg of both

the row and columns on the query.

4. Action Query: it is used to perform on action on record that meets the criteria

specified in the query object.

5. SQL Query: it is created using SQL statement is a database query language that

can be used to specify multiple table joins on the bass of foreign key record

selection oriented and data grouping.

Ques4: Write steps to create form using wizard and through Auto format.

Ans: Form through wizard 1. Select form tab form database object tabs in database window.

2. Click crate form by using wizard.

3. A dialogue box named form wizard: A dialogue box named form wizard appears

on the screen in which select your form table Queries combo box.

4. After that select the field of the table which you would line to include in the form

use < or > to more a single field and << or >> to move all the fields after that

press next.

5. There appeared a dialogue box that show a list of various types of forms layout

like columns tabular datasheet, justified etc. Select any one of them then press.

Next button.

6. In the next dialogue box select the style of the form the given list of bytes. Then

press next button.

7. In the next window five the title to your form and then press finish button.

Forms using auto form 1. Click on form in database object tab in database window.

2. There appear an icon named ”new” in the toolbar of the database window click

on new.

3. A dialogue box named new form appears choosing various options to prepare

form select.

• Auto form: columnar

• Auto form: Tabular



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• Auto form: Datasheet 4. This dialoged box also asks the table name on which you have to prepared report

select appropriate table name form the list.

5. After that appears a form showing field of the selected table or query.

6. It the format chosen is columnar then the files are show in columnar then the files

are shown in columnar format and you can insert the data one by one for each

tupple you can move forward and backward by using or button retentively the

record number show in between these buttons tells which record number your are

viewing.

• The form in columnar format: It show having 5 record to insert new record

click > button 4 times to insert sixth record and if you want to see any previous

record press < button. After inserting record save the form by clicking file –then

save or by pressing ctrl +s or save icon on tool bar.

• If the format chosen is tabular: Then the fields are shown in tabular format.

Again you can move backward, forward and by using > and < buttons

respectively. The record number again shown at which record number again

shown at which record number you are inserting value.

Again the button has the same functioning at present we at data number of 2.

• If you choose the data sheet & as you in insert data inv the datasheet in same way

you insert data in the datasheet in same way you insert data in same way you

insert data in the form.

Ques5: what do you mean reports in MS-ACCESS write steps to create report

using wizard and using auto report.

Ans: A report is an effective way to present your data in a printable format. It provide

a flexible way of viewing and printing summary information with the help of report

we can have detained information at the required level picture, graphics, statically

evaluated can be inserted in report to mark it more printable.

The information on a report may be derived table queries report are used for:- 1. Presenting information in a customized way both on screen and on paper.

2. Grouping and sorting data according to your need and in order toy want.

3. Calculating avg, fields’ tool and drawing groups.

Important point to be kept in mind while planning for reports:

Generally hard copy of the report is used to communication database information

with manager, Employee and client. A clearly designed and well organized report is

required to present the database information in an effective manner >

Following point should be kept in mind while designing a report. 1. Identify a meaningful title for the report.

2. Determine he fields and members that the report will present.

3. Decide how those fields should be sorted and grouped within the report.

4. Determine how the records should be sorted a grouped within the report.



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5. Identify any other description information that should be placed at the end of

the report or at the top or bottom of each page of report.

Type of report 1. Tabular reports

2. Columnar report

3. Mailing labels.

Reports using wizard 1. Click on report on the database object tab of database window.

2. Click on create report by using wizard.

3. After that a dialogue box named report wizard appear on the screen in which

select your report from table/ queries combo box.

4. After that select the fields of the table which you would like to include in the

form. Use< and > to move b/w records.

5. Then appears a dialogue box that requires grouping information select the

fields which will be used for grouping the record. Click next button.

6. Then a dialogue box appears in which you can give sorting information. You

can sort your data for sport in ascending or descending order. Click next to

more ahead.

7. Next dialogue box lets you select tabular layout or portrait orientation select

which you like and click next.

8. Now select the print style of the report form the built in list click next.

9. Give name to report and click finish button. Finally report will be presented

on your screen.

Report using auto report.

1. Click on report in database object tab in database window.

2. There appears on icon named new or click inserts then form.

3. A dialogue box named new report appearing having various new option to

prepare the report select.

• Auto report: columnar

• Auto Report: Tabular



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Technology

Database management system