If you look at the large variety of
SQL commands, they can be divided into three large subgroups. Data Definition
Language deals with database schemas and descriptions of how the data should
reside in the database, therefore language statements like CREATE TABLE or
ALTER TABLE belong to DDL. DML deals with data manipulation, and therefore
includes most common SQL statements such SELECT, INSERT, etc. Data Control
Language includes commands such as GRANT, and mostly concerns with rights,
permissions and other controls of the database system.
No comments:
Post a Comment