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Commands In SQL

 

Data Definition Language (DDL):

These commands are used to define the database schema.

 

The following commands are used in DDL:

 

  • CREATE: Used in the creation of a database.
  • DROP: Used in the deletion of objects from the database.
  • ALTER: Used in the alteration of the structure of the database.
  • TRUNCATE: Used for the deletion of all the records from the table.
  • COMMENT: Used in the addition of comments to the database dictionary.
  • RENAME: Used in the renaming of an existing object in the database.

 

Data Query Language (DQL)

 

These commands are used for performing queries on data.

 

 

  • SELECT: It is used to retrieve data from the database.

 

 

Data Manipulation Language (DML)

 

These commands are used to manipulate the data present in the database.

 

 

  • INSERT : This command is used to insert data into the table
  • UPDATE: This command is used to update existing data into the table.
  • DELETE: This command is used to delete objects from the table.
  • SELECT : This command selects attributes from relations.

 

 

Data Control Language (DCL)

 

These commands control the database system

 

  • GRANT : Gives the user access to the database.
  • REVOKE : Withdraws the user access to the database.

 

Transaction Control Language (TCL)

 

These commands control the transaction within the database

 

  • COMMIT: Permanently commits a transaction
  • ROLLBACK: In case of an error, it rolls back the transaction
  • SAVEPOINT : A savepoint is set within a translation.
  • SET TRANSACTION: The characteristics of a transaction are specified

 

Reference :

Commands in DDL.