DELETE FROM teacher WHERE id_tch=105

CREATE VIEW V2( nam, snam, subj, mark) AS select student.sname, student.name, subject.name, progress.mark from student, subject, progress where student.id_stud=progress.id_stud and subject.id_subj=progress.id_subj

CREATE TABLE T2 (F2 INTEGER REFERENCES T1(P1) ON UPDATE CASCADE

ON DELETE SET NULL)

ALTER TABLE teacher ADD thc_sal DECIMAL (7,2)

CREATE DOMAIN NAM AS VARCHAR (30)