ALTER TABLE table_name action; -- ADD column_name datatype; -- ALTER COLUMN column_name new_datatype; -- RENAME COLUMN old_column_name TO new_column_name; -- DROP COLUMN column_name; -- ADD CONSTRAINT pk_constraint_name PRIMARY KEY (column_name); -- ADD CONSTRAINT fk_constraint_name FOREIGN KEY (column_name) REFERENCES other_table (other_column); -- DROP CONSTRAINT constraint_name;