ALTER
command is used for various purposes in RDBMS.
- Rename table
Syntax – ALTER TABLE table_name RENAME TO rename_table_name;
- Add a new field(column) into table
Syntax – ALTER TABLE table_name ADD COLUMN attribute_names datatype(size);
- Drop a field(column) from table
Syntax – ALTER TABLE table_name DROP COLUMN attribute_name;
- Modify any filed(column) of a table
Syntax – ALTER TABLE table_name MODIFY attribute_name datatype(size);
- Add primary key into field of a table
Syntax – ALTER TABLE table_name ADD PRIMARY KEY (attribute_name);
- Auto_increment any field.
Syntax – ALTER TABLE table_name AUTO_INCREMENT=?;
