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Types of SQL Commands

 

Types of SQL Commands

SQL: SQL commands are used for communicating with the database. There are a total of 5 types of SQL commands

1. DDL (Data Definition Language)

2. DML (Data Manipulating Language)

3. DCL (Data Control Language)

4. TCL (Transaction Control Language)

5. DQL (Data Query Language)



1. DDL (Data Definition Language): Data Definition Language helps us to define database structure.

·      Create: Create statement is used to define a database.

·      Drop: Drop statement is used to remove the table and database from RDBMS.

·      Alter: Alter statement is used to add, delete or modify columns in an existing table.

·      Truncate: Truncate command is used to delete all the records from the table and free the space containing the table.

2. DML (Data Manipulating Language): Data Manipulating Language allows us to modify the database instance.

·      Insert: Insert statement is used to insert data in the MYSQL table.

·      Update: Update command is used to update the existing records in a table.

·      Delete: Delete command is used to remove one or more records from a table.

3. DCL (Data Control Language): Data Control Language is used to grant and take back "rights & permissions" from any other database user.

·      Grant: Grant command is used to provide access or privileges on the database objects to the users.

There are two types of privileges

1. System Privileges(CREATE, ALTER, DROP)

2. Object Privileges(EXECUTE, SELECT, INSERT, UPDATE OR DELETE)

 

·      Revoke: Revoke command is used to take back access or privileges from the user.


4. TCL (Transaction Control Language): Transaction Control Language deals with the transaction within the database. These commands can only use with the Data Manipulating Commands.

·      Commit: Commit command is used to save all the changes to the database.

·      Rollback: Rollback command allows us to undo transactions that have not been saved to the database.

·      SavePoint: Savepoint command helps us to set a savepoint within a transaction.  


5. DQL (Data Query Language): This command helps us to fetch the data from the database.

·    Select:  Select command is used to fetch the data from the MySQL database.


 

 

                                            

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