What Does SQL Stand For
SQL stands for Structured Query Language. SQL is a tool for database management that provides function like organizing, managing and retrieving data stored in computer memory in the form of database. The SQL is pronounced as 'sequel'. SQL is a language that interacts with database by performing requested function. SQL performs all these functions on a specific type of database called Relational Database. And the program that stores and manages all the information stored in the computer memory in the form of database is called Database Management System (DBMS).
Definition of SQL
Basic Functions of SQL
SQL functionality is similar to database management systems to control the data stored in the computer database:
1. Data Management Functions
- Data Definition: Structure and organization can be defined using SQL. You an also create well defined relational structure of database.
- Data Manipulation: You can add, modify or delete the data items using SQL.
- Data Retrieval: SQL also allows you to request for data from the database and retrieve the required results.
2. Data Security Functions
- Data Access: You can grant permission/authorization to the database users for accessing and manipulating the data stored using SQL.
- Data Sharing: SQL is used to share data between concurrent users without any conflict.
- Data Integrity: You can apply constraints to retain the database consistency while any alteration done to the database.
Basic SQL Commands for Data Manipulation
SELECT : to retrieve data
INSERT : to insert new row
DELETE : to delete the rows from the database
UPDATE : to modify the existing data
SQL Commands for Data Definition
CREATE TABLE : to add new table into the database
DROP TABLE : to delete a table from the database
ALTER TABLE : to modify the previous table structure
CREATE INDEX : to bind a new index with a column
DROP INDEX : to delete the index of column
CREATE VIEW : to add a view for database table
DROP VIEW : to delete the existing view of any table
Access Control Commands
GRANT : to grant access privileges to the database users
REVOKE : to remove access privileges from the database users
To retrieve the desired results from the requested SQL query some clauses are also used to filter the records from the results retrieved. Following are some clause commonly used to filter the results: