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DATABASE MANAGEMENT SYSTEM

Database is a collection of related data.
Data is known as facts that can be recorded and have an implicit meaning.
Mini-world is some part of the real world about which data is stored in a database. For example, student grades and transcripts at a university.
Database Management System (DBMS) is a software package/ system to facilitate the creation and maintenance of a computerized database.
OR
Database Management System (DBMS) is a special software system programmed to know which data elements each user is authorized to access and deny unauthorized requests of data. Database System is the Database Management System (DBMS) software together with the data itself. Sometimes, the applications are also included.
The purpose of the Database Management System (DBMS)is to provide controlled access to the database.
    Database Management System (DBMS)Features
  1. User Programs : makes the presence of the DBMS transparent to the user
  2. Direct Query allows :authorized users to access data without programming
  3. Application Development : user created applications
  4. Backup and Recovery : copies database
  5. Database Usage Reporting : captures statistics on database usage (who, when, etc.)
  6. Database Access : authorizes access to sections of the database
    Database Languages
  1. Data Definition Language (DDL)
  2. Data Manipulation Language (DML)
  1. Data Definition Language (DDL)
  2. DDL is a programming language used to define the database to the DBMS. The DDL identifies the names and the relationship of all data elements, records, and files that constitute the database. Viewing Levels: internal view - physical arrangement of records (1) conceptual view - representation of database (1) user view - the portion of the database each user views (many)
  3. Data Manipulation Language (DML)
  4. DML is the proprietary programming language that a particular DBMS uses to retrieve, process, and store data. Entire user programs may be written in the DML, or selected DML commands can be inserted into universal programs, such as COBOL and FORTRAN.
      Two types of Data Manipulation Language (DML):-
    1. Procedural
    2. Procedural
    1. Procedural DML
      It equires a user to specify what data are needed and how to get those data.
    2. Procedural DML (Nonprocedural DML)
      It requires a user to specify what data are needed without specifying how to get those data.