Explain SQL Commands and its types.

Sql commands are the set of instructions which are connect/ interact with database to perform specific task. SQL commands are instructions, coded into SQL statements, which are used to communicate with the database to perform specific tasks, work, functions and queries with data.

Types of Sql command:

 Sql commands are grouped into five (5) major categories depending on their functionality.

1). DDL: DDL stand for Data Definition Language. These commands are used to creating, modifying, and dropping the structure of database objects. The examples of DDL commands are CREATE, ALTER, DROP, RENAME and TRUNCATE.

2). DQL: DQL stand for Data Query Language. DQL commands are used to retrieve the data from database tables. SELECT is the only example of DQL commands.

3). DML: DML stand for Data Manipulation Language. These commands are used to retrieve, store, modify, and delete data in database tables. The examples of DML commands are UPDATE, INSERT and DELETE.

4). TCL: TCL stand for Transaction Control Language.  TCL commands are used to manage the changes made by DML statements. Examples of DCL command are COMMIT, ROLLBACK, and SAVEPOINT.

5). DCL: DCL stand for Data Control Language. DCL commands are used to implement security on database objects. Examples of DCL command are GRANT and REVOKE.