SQL stands for Structured Query Language and used to manipulate data in database. SQL is a standard language for all relational database like MySQL , ORACLE database, SQL Server etc.
Uses of SQL:
- It is used to access data in a RDBMS.
- It is used to describe the data in a Rdbms.
- It is used to define and manipulate the data in database that data.
- It is used to create, alter and drop databases and tables.
- It is used to create view, stored procedure, functions, index in a database.
- It is used to create users/schema and their respective profiles in the database.
- It is used to set permissions on tables, procedures, and views in a database.
What is a Database?
A database is an organised collection of data/information so that it can be easily accessed, managed and modified.
What is DBMS?
DBMS stands for database management system is a software that is used to define, create, query, update, and administration of databases.
What is RDBMS?
RDBMS is stands for relational database management system where data is stored in form of Relational Tables.A RDBMS is based on the relational model as invented by E. F. Codd.
Basically all SQL commands falls into four category:
- DML : Data Manipulation Language, used to insert, update, retrieve and delete the data in a database table.
- DDL : Data Definition Language, used to create, alter and drop tables and other database objects.
- DCL : Data Control Language, used for access and data control to database users.
- TCL : Transaction Control Language, used for transaction control.
Data Manipulation Language (DML)
|SELECT||Used to retrieves certain records from one or more tables.|
|INSERT||Used to insert a record/row in a table.|
|UPDATE||Used to modify records.|
|DELETE||Used to delete records.|
Data Definition Language (DDL)
|CREATE||Used to create a new table, view , or other database objects.|
|ALTER||Used to modify a database object, such as a table.|
|DROP||Used to delete an entire table, a view of a table or other database objects.|
Data Control Language (DCL)
|GRANT||Used to give a privilege to user like create table, use session, create schema etc.|
|REVOKE||Used to take back privileges granted for a user.|
Transaction Control Language (TCL)
|COMMIT||Used to commit or save a transaction at a particular point of time permanently|
|SAVEPOINT||Used to save a transaction temporarily at a particular point, so that it can be rolled back.|
|ROLLBACK||Used to rollback to a temporarily saved point of transaction.|