558_____________________________________________ 10

  ,       . 
 , ,    Pers  , -
     Dep    , 
  Dep.     :

/*   Dep */
create table Dep(

Dep char(15) Not Null Primary Key,

Proisv char(1)
) ;

/*   Pers */
create table Pers(

Mum 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,

CONSTRAINT Dep CHECK(EXISTS(

SELECT Dep FROM Dep WHERE Pers.Dep = Dep.Dep))
) ;

   CONSTRAINT    Dep  ,
        .  -
      ,    Dep  Pers
     Dep  Dep.

      .  -
   Drop Table:

DROP TABLE < >

 ,           
.        ( ) , 
 Drop Table   .

     
Alter Table:

ALTER TABLE < > <> < > < > .. .

   <>    ADD   -
 ,  DROP    .   ,  
   < >.   ,     -
.     :

ALTER TABLE Pers DROP Year_b, ADD Age integer

10.1.5   

       
.    Select    ORDER
BY,           -
          -
.          -
  .       ,  
ORDER BY     ,  -   . -
,      1, 2, ,    

Select ... ORDER BY pl,p2