PowerPoint Presentation : Neenu Prasad DATABASE
Definition : Definition Data: facts that can be recorded and that have implicit meaning. A database is a collection of interrelated data , typically describing the activities of one or more related Organizations and is used for managing large bodies of information.
Example : Example A university database might contain information about the following: Entities such as students, faculty, courses, and classrooms. Relationships between entities, such as students' enrolment in courses, faculty teaching courses, and the use of rooms for courses
DATABASE MANAGEMENT SYSTEMS(DBMS) : DATABASE MANAGEMENT SYSTEMS(DBMS) general-purpose software system Collection of inter related data programs to manage the data. +
Well known DBMS : Well known DBMS Oracle IBM DB2 Microsoft SQL Server Microsoft Access PostgreSQL MySQL SQLite
PowerPoint Presentation :
Users : Users Users are differentiated by the way they expect to interact with the system.. Naïve users : They invoke one of the permanent application programs that have been written previously .
Users : Users S ophisticated users : They form requests in a database query language.ie they interact with the systems without writing application programs. Application programmers : They are computer professionals who write the application programs. They can choose from many tools to develop user interfaces
Database Administrator (DBA) : Database Administrator (DBA) Coordinates all the activities of the database system. good understanding of the enterprise’s information resources and needs.
Functions of DBA : Functions of DBA Schema definition Storage structure and access method definition Schema and physical organization modification Granting user authority to access the database Specifying integrity constraints Acting as liaison with users Monitoring performance and responding to changes in requirements
Query Processing : Query Processing It includes 1. Parsing and translation 2. Optimization 3. Evaluation
Cont… : Cont… a ) DDL Interpreter (Parsing and Translation): Interprets the DDL statements and records the definition in the data dictionary. Data dictionary is a special type of table that can be accessed and modified only by the DB itself. b) DML Complier (Query Optimisation): Translates DML statements into an evaluation plan consisting of low level instruction that query evaluation engine understand. c) Query Evaluation Engine (evaluation): Executes the low level instructions generated by DML compiler.
Storage Manager : Storage Manager program module that provides the interface between the low level data stored in db and application programs and queries submitted to the system.
Storage Manager : Storage Manager Authorisation and integrity manager They performs tests for satisfaction of integrity constraints and checks for the authority of users to access data. Transaction manager Ensures that the database remains in a consistent state. File manager Manages the allocation of space on disk storage and the structures used to represent information stored on disk. Buffer Manager Responsible for fetching data from disk storage into main memory
APPLICATIONS OF DATABASES : APPLICATIONS OF DATABASES Banking: all transactions Airlines: reservations, schedules Universities: registration, grades Sales: customers, products, purchases Online retailers: order tracking, customized recommendations Manufacturing: production, inventory, orders, supply chain
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