         557

NO ACTION           -
      


CASCADE            
      ;  -
       -
        

SET DEFAULT        -
       
   

SET NULL            -
 NULL

  ,     ,  , -
,      Dep   Dep  -
,    .   Pers  -
      Dep  ,    . 
  (    )  
         
  .       ON
UPDATE CASCADE.    (   
) , -,  .    ON
DELETE CASCADE,      Pers,    -
,  , ..     -
     . ,   ,   
      
    .    ON DELETE
SET NULL.       
   NULL   Dep.     -
      .   NULL
    , ,    Pers
     Dep. ,    -
  ON DELETE SET DEFAULT,   Pers   Dep 
   (, )     Dep -
      Dep.  ,   -
,   :

/*   Dep */
create table Dep(

Dep char(15) Not Null Primary Key,

Proisv char(l)
);

/*   Pers */
create table Pers(

Num smallint Not Null Primary Key,

Dep char(15) DEFAULT "",

Fam char(20) Not Null,

Nam char(20) Not Null,

Par char(20) Not Null,

FOREIGN KEY (Dep) REFERENCES Dep
ON DELETE SET DEFAULT ON UPDATE CASCADE,

        
 .  ,         