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Disclaimer: This presentation is prepared by trainees of baabtra as a part of mentoring program. This is not official document of baabtra –Mentoring PartnerBaabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt . Ltd
DATABASES AND
TYPES OF DATABASES AVAILABLE IN THE MARKET
Jaseena A [email protected]/Jaseena
Muhammed A Ptwitter.com/usernamein.linkedin.com/in/profilename9539443588
DRAWBACKS OF USING FILESYSTEM
Data redundancy and inconsistencyMultiple file formats, duplication of information in different files
Difficulty in accessing data Need to write a new program to carry out each new task
Data isolation — multiple files and formatsIntegrity problems
DRAWBACKS OF USING FILESYSTEMAtomicity of updates
• Failures may leave database in an inconsistent state with partial updates carried out
o E.g. transfer of funds from one account to another should either complete or not happen at all
Concurrent access by multiple users• Concurrent access needed for performance• Uncontrolled concurrent accesses can lead to
inconsistenciesE.g. two people reading a balance and updating it at the same time
Security problems
What is a database? It’s an organized collection of data.
A database management system (DBMS) such as Oracle or SQL Server which provides us with the software tools we need to organize that data in a flexible manner. It includes tools to add, modify or delete data from the database, ask questions (or queries) about the data stored in the database and produce reports summarizing selected contents.
What is a database?•A database represents some aspect of the real world, sometimes called the mini-world or the Universe of Discourse (UoD).
•A database is a logically coherent collection of data with some inherit meaning.
A random assortment of data cannot correctly be referred to as a database.
•A database is designed, built, and populated with data for a specific purpose. It has an intended group of users and some preconceived applications in which these users are interested
Data vs. information:What is the difference?
What is data?Data can be defined in many ways. Information science defines data as unprocessed information.
What is information?• Information is data that have been
organized and communicated in a coherent and meaningful manner.
• Data is converted into information, and information is converted into knowledge.
• Knowledge; information evaluated and organized so that it can be used purposefully.
What is DBMS? A very large, integrated collection of data.
Models real-world Entities (e.g., students, courses,Teacher) Relationships (e.g., Teena teaching Alex)
A Database Management System (DBMS) is a software package designed to store and manage databases.
What is DBMS?Collection of interrelated data
Set of programs to access the data
DBMS contains information about a particular enterprise
DBMS provides an environment that is both convenient and efficient to use.
Database Applications:• Banking: all transactions• Airlines: reservations, schedules• Universities: registration, grades
TYPES OF DBMS
1. RDBMS2. OODBMS3. Network DBMS4. Hierarchical DBMS
Object oriented database management systems (OODBMSs) combine database capabilities with object-oriented programming language capabilities.
OODBMSs allow object-oriented programmers to develop the product, store them as objects, and replicate or modify existing objects to make new objects within the OODBMS.
Because the database is integrated with the programming language, the programmer can maintain consistency within one environment, in that both the OODBMS and the programming language will use the same model of representation. Relational DBMS projects, by way of contrast, maintain a clearer division between the database model and the application.
OODBMS
OODBMS
Hierarchical dbms The hierarchical data model organizes data in a tree structure.There is a hierarchy of parent and child data segments. This structure implies that a record can have repeating information, generally in the child data segments.
Data in a series of records, which have a set of field values attached to it. It collects all the instances of a specific record together as a record type.
These record types are the equivalent of tables in the relational model, and with the individual records being the equivalent of rows. To create links between these record types, the hierarchical model uses Parent Child Relationships.
Hierarchical dbms For example, an organization might store information about an
employee, such as name, employee number, department, salary. The organization might also store information about an employee's children, such as name and date of birth. The employee and children data forms a hierarchy, where the employee data represents the parent segment and the children data represents the child segment. If an employee has three children, then there would be three child segments associated with one employee segment.
In a hierarchical database the parent-child relationship is one to many. This restricts a child segment to having only one parent segment.
Hierarchical dbms
Network DBMS The popularity of the network data model coincided with the
popularity of the hierarchical data model. Some data were more naturally modeled with more than one parent per child. So, the network model permitted the modeling of many-to-many relationships in data
Network DBMS
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