Structured Query Language (SQL)

Structured Query Language (SQL)

A database is a collection of integrated data organized as bytes, fields, records, and files. A database Management system is a computer-based system for defining, creating, manipulating, controlling, managing and using databases. DBMS provides:

  • Improved data integrity
  • Independence
  • Reduced data redundancy.

Structured Query Language (SQL)

There are a number of database query languages in use, either commercially or experimentally. SQL however, is the most widely used among these languages. It is a standard computer language for relational database management and data manipulation. SQL is the most influential commercially marketed query language. SQL uses a combination of relational-algebra and relational-calculus construct. This is not joisted query language; it can define the structure of the data, modify data in the database and specify security constraints. SQL has become the standard relational database language.

The SQL language has several parts:

Data Definition-Language (DDL): The SQL DDL provides commands for defining relation schemas, deleting relation schemas, modifying relation-schemas and creating tables.

Data Manipulation Language (DML): The SQL DML, includes commands to insert into, delete entities from and modify (update) entities in the database.

Advantages −

  • Allows users to access, describe and manipulate data in the relational database management systems.
  • Allows embedding within other languages using SQL modules, libraries & pre-compilers.
  • Allows users to create a view, stored procedure, functions in a database.
  • Allows users to set permissions on tables, procedures, and views.