Data Control Language (DCL). DCL handles the authorisation aspects of data and permits the user to control who has access to see or manipulate data within the database.
Its two main keywords are:
GRANT - authorises a user to perform an operation or a set of operations e.g. grant all privileges to user X.
REVOKE - removes or restricts the capability of a user to perform an operation or a set of operations.
The task of DDL is database definition, i.e. the predefinition and manipulation of the metadata.
Using different DDL commands, the database metadata can be created, altered and deleted. For example table structure, use of indices, the activation of exceptions and construction of procedures can all be defined by DDL commands. DDL commands are a subarea of SQL; the range of the SQL language is composed of DDL and DML together.
DML - Data Manipulation Language
DML is the abbreviation for Data Manipulation Language. DML is a collection of SQL commands that can be used to manipulate a database's data.
DML is part of the SQL language commands, which execute queries with database objects and changes to their contents. The various DML commands can be used to create, edit, evaluate and delete data in a database.
DML commands are a subarea of SQL; the range of the SQL language is composed of DML and DDL together.