DML , . DML: INSERT (), UPDATE (), DELETE ().
INSERT
SQL INSERT. INSERT :
CREATE TABLE, , . ANSI . , 3 , 2 + 1 . , 1, 2 ..
(NULL), , :
__1 _ NULL. NULL , , .
INSERT, , . , VALUES ( ) :
, __2 , , , __1. , __1 :
1) CREATE TABLE;
2) , __2 , , , ( ).
, , , , , __2. __1 , __2. __2 , __1.
DELETE
DELETE . , , . __1, :
DELETE FROM __1;
, , DROP TABLE (. ). . , , , :
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DELETE FROM __1 WHERE ;
, . , .
UPDATE
UPDATE. UPDATE, , SET, , , WHERE, .
UPDATE _
SET __1 = __1, __2 =
__2,... WHERE ;
, WHERE . , SET . , :
SET _._ = _
UPDATE, :
SET _ = _ .
SQL . SET UPDATE. VALUES INSERT, .
UPDATE _ SET _ = _ * 2
. SET , - UPDATE.
SET NULL:
UPDATE _ SET _ = NULL WHERE ; _ , _, .
10.
SQL , , . , . , . . , SELECT SELECT , , (). , , , ? , , . SQL , , , . SQL- , . , . , . , . DECLARE CURSOR :
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EXEC SQL DECLARE CURSOR _ FOR
SELECT *
FROM _
WHERE ;
; . , , , . : , . ORDER BY - , - .
, :
EXEC SQL OPEN CURSOR _;
, , DECLARE FETH. FETCH :
EXEC SQL FETCH _ INTO: _1, _2, ;
. FETCH . , FETCH , , , , , , , , , , , .
CLOSE CURSOR, OPEN CURSOR:
EXEC SQL CLOSE CURSOR _;