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Data Manipulation Language (DML)

Data Manipulation Language (DML)

Data Manipulation Language (DML) is used for data manipulation.

Data manipulation is
          Retrieval of Information Stored in Database
          Insertion of Information to the database
          Deletion of information from the database
          Updating of information stored in the databas


Types of Data Manipulation Language (DML) 
              Procedural DML
              Declarative DML (Non Procedural DML)

Procedural DML:
In procedural Data manipulation language user has to specify what data are needed and how to get it.

Declarative DML (Non Procedural DML):
In declarative
Data manipulation language user has to specify what data are needed without specifying how to get it.
Example : SQL (Structured Query Languages)

Data Definition Language (DDL)

Data Definition Language (DDL)   

We specify the database schema (Data fields , Data Types , Constraints) by a set of definition expressed by a language called DDL.

Example: CREATE TABLE student(SNAME  CHAR(10), ROLLNO CHAR(10)).

This DDL statement creates a table student with fields SNAME and ROLLNO.This information (meta data) is stored in the data dictionary.

Database System Environment

 Database System Environment

The term database system refers to an organization of components that define and regulate the collection, storage, management, and use of data with in a database environment. In a high level view the database system is composed of the following five major parts.

  • Hardware
  • Software 
  • People 
  • Procedures
  • Data