modifier table
ALTER TABLE table_name MODIFY COLUMN column_name datatype;
Bright Buffalo
ALTER TABLE table_name MODIFY COLUMN column_name datatype;ALTER TABLE table_name MODIFY column_name datatype NOT NULL;ALTER TABLE table_name
ADD CONSTRAINT MyPrimaryKey PRIMARY KEY (column1, column2...);ALTER TABLE table_name
DROP PRIMARY KEY;ALTER TABLE table_name
ADD CONSTRAINT MyUniqueConstraint UNIQUE(column1, column2...);ALTER TABLE table_name
DROP INDEX MyUniqueConstraint;ALTER TABLE table_name
ADD CONSTRAINT MyUniqueConstraint CHECK (CONDITION);ALTER TABLE table_name
DROP CONSTRAINT MyUniqueConstraint;