Chapter # 04Information and Databases Information and Database

Chapter # 04Chapter # 04 Information and DatabasesInformation and Databases

Information and DatabaseInformation and Database


DatabaseDatabase

““Is an organized collection of records/information Is an organized collection of records/information that is made-up of related records.”that is made-up of related records.”

““Refers to a structured collection of electronically Refers to a structured collection of electronically stored data which is controlled, accessed through stored data which is controlled, accessed through

computers based on predefined relationships computers based on predefined relationships between predefined types of data items related to between predefined types of data items related to

a specific business situation or problem”a specific business situation or problem”


Database Management System :Database Management System : A DBMS is an A DBMS is an integrated set of programs used to define, update integrated set of programs used to define, update

and control databases.and control databases.

File :File : Is a set of related records that contains the Is a set of related records that contains the same fields in the same order and same format.same fields in the same order and same format.

Record :Record : Record is a set of fields, each of which is Record is a set of fields, each of which is related to the same thing, person or event. related to the same thing, person or event.

Key :Key : A key is field that uniquely identifies which A key is field that uniquely identifies which person, thing or event the record describes. person, thing or event the record describes.

Field :Field : A field is a group of characters that have a A field is a group of characters that have a predefined meaning. predefined meaning.


Types of DataTypes of Data

Pre-defined data ItemsPre-defined data Items

TextText

ImagesImages

AudioAudio

VideoVideo


Data Modeling : Data Modeling : The process of defining what data The process of defining what data is used or produced in an information system and is used or produced in an information system and how that data is organized.how that data is organized.

Entities :Entities :The specific things, database collects data The specific things, database collects data about.about.

Entity type :Entity type :The kind of things, data is collected aboutThe kind of things, data is collected about

Relationship :Relationship :The way specific entities of one type The way specific entities of one type might related to specific entities of the other typemight related to specific entities of the other type


Entity Relation Diagram :Entity Relation Diagram :Technique for identifying the Technique for identifying the entity types in a situation and diagramming the entity types in a situation and diagramming the relationship between those entity types. relationship between those entity types.

Type of Relationships :Type of Relationships :

•One-to-One relationshipOne-to-One relationship

•One to Many relationshipOne to Many relationship

•Many to Many relationsMany to Many relations

Relational Structure of Databases Relational Structure of Databases

Primary Key Filed:Primary Key Filed:A column which uniquely identifies a in a table A column which uniquely identifies a in a table

Foreign Key: Foreign Key: Which refer to a specific record of an other table.Which refer to a specific record of an other table.

Properties of Key Field : Properties of Key Field : Unique, Not Null, and IndexedUnique, Not Null, and Indexed

Data Modeling – Entity Relation DiagramData Modeling – Entity Relation Diagram

Data Modeling – Entity Relation DiagramData Modeling – Entity Relation Diagram


Types of DatabasesTypes of Databases

Relational DatabsesRelational DatabsesMulti-Dimensional DatabasesMulti-Dimensional DatabasesData WarehouseData WarehouseGeographical Information systemsGeographical Information systemsText and Image databasesText and Image databasesHyper Databases and WebHyper Databases and Web

Web pageWeb pageHTMLHTMLURLURL

Indexes and Search EnginesIndexes and Search Engines

Data W

arehousingD

ata Warehousing


Roles of DBMSRoles of DBMS

Controlling and Organizing data to increase its valueControlling and Organizing data to increase its value Efficient way to organize dataEfficient way to organize data Improves data AccuracyImproves data Accuracy Discouraging Data RedundancyDiscouraging Data Redundancy FlexibilityFlexibility Supports Data Security (controlled access / recovery procedures)Supports Data Security (controlled access / recovery procedures)

Making Programming more efficientMaking Programming more efficient Provides consistent and centralized defining methodsProvides consistent and centralized defining methods


Range of DBMS FunctionsRange of DBMS Functions

Defining the databaseDefining the database Data DefinitionData Definition Data DictionaryData Dictionary

Methods of Accessing data in a Computer SystemsMethods of Accessing data in a Computer Systems Sequential AccessSequential Access Direct AccessDirect Access Indexed Sequential Access (ISAM)Indexed Sequential Access (ISAM)

Processing transactionsProcessing transactions Controlling Distributed DatabasesControlling Distributed DatabasesBackup and RecoveryBackup and RecoverySupporting Database Administration Supporting Database Administration


Evaluating Data as a Source (Usefulness)Evaluating Data as a Source (Usefulness)

Information Quality :Information Quality : Accuracy Accuracy PrecisionPrecision CompletenessCompleteness AgeAge TimelinessTimeliness SourceSource

Information Accessibility:Information Accessibility: AvailabilityAvailability AdmissibilityAdmissibility

Information Presentation :Information Presentation : Level of SummarizationLevel of Summarization FormatFormat

Information Security :Information Security : Access RestrictionAccess Restriction EncryptionEncryption


Models as Component of ISModels as Component of IS

Mental Models Mental Models

Mathematical ModelMathematical Model

What-if QuestionsWhat-if Questions

Virtual Reality :Virtual Reality :The Ultimate interactive ModelThe Ultimate interactive Model

Documents

Chapter # 04Information and Databases Information and Database