What are the different commands used in MySQL?

MySQLMySQLi Database

SQL language is divided into four types of primary language statements: DML, DDL, DCL and TCL. Using these statements, we can define the structure of a database by creating and altering database objects and we can manipulate data in a table through updates or deletions. We also can control which user can read/write data or manage transactions to create a single unit of work.

The four main categories of SQL statements are as follows −

DML (Data Manipulation Language)

DML statements affect records in a table. These are basic operations we perform on data such as selecting a few records from a table, inserting new records, deleting unnecessary records, and updating/modifying existing records.

DML statements include the following −

SELECT – select records from a table

  • INSERT – insert new records
  • UPDATE – update/Modify existing records
  • DELETE – delete existing records

DDL (Data Definition Language)

DDL statements are used to alter/modify a database or table structure and schema. These statements handle the design and storage of database objects.

  • CREATE – create a new Table, database, schema
  • ALTER – alter existing table, column description 
  • DROP – delete existing objects from database

DCL (Data Control Language)

DCL statements control the level of access that users have on database objects.

  • GRANT – allows users to read/write on certain database objects
  • REVOKE – keeps users from read/write permission on database objects

TCL (Transaction Control Language)

TCL statements allow you to control and manage transactions to maintain the integrity of data within SQL statements.

  • BEGIN Transaction – opens a transaction 
  •  COMMIT Transaction – commits a transaction 
  •  ROLLBACK Transaction – ROLLBACK a transaction in case of any error
raja
Published on 19-Feb-2018 08:03:44
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