[Oracle] 解析Oracle中多表级联删除的方法

CREATE TABLE "U_WEN_BOOK"."FARTAB" ("FAR_ID" NUMBER(10) NOT NULL,
"FAR_NAME" VARCHAR2(10), "OTHER_NAME" VARCHAR2(10), 
CONSTRAINT "PK_FER" PRIMARY KEY("FAR_ID")) 
CREATE TABLE "U_WEN_BOOK"."CHILTAB" ("CHIL_ID" NUMBER(10) NOT 
  NULL, "CHIL_NAME" VARCHAR2(10), "CHIL_OTHER" VARCHAR2(10), 
  "FAR_ID" NUMBER(10) NOT NULL, 
  CONSTRAINT "PK_CHIL" PRIMARY KEY("CHIL_ID"), 
  CONSTRAINT "FK_CHIL" FOREIGN KEY("FAR_ID") 
REFERENCES "U_WEN_BOOK"."FARTAB"("FAR_ID") ON DELETE CASCADE)

ALTER TABLE "U_WEN_BOOK"."GCHILTAB1" 
  DROP CONSTRAINT "FK_G1"
ALTER TABLE "U_WEN_BOOK"."GCHILTAB1" 
  ADD (CONSTRAINT "FK_G1" FOREIGN KEY() 
  REFERENCES "U_WEN_BOOK"."CHILTAB"() 
  ON DELETE CASCADE) 
（这样就可以级联删除了，删除完后，如果不放心这样的约束条件，并且不嫌麻烦可以再重建为不带级联删除等外键约束，防止误操作）

create   table orderCombine   (   
O_Id           VARCHAR2(16)   not   null,   
OrderId       VARCHAR2(15)   not   null,             
FormerId     VARCHAR2(16)   not   null,   
constraint   PK_ORDERCOMBINE   primary   key   (FormerId) );
   create   table   VIPForm   (   
V_Id           VARCHAR2(16)     not   null,         
IsValid       CHAR(1)   default   '0'   not   null   ,           
Constraint fk_vipform foreign key(V_id)   references   ordercombine(formerid) );   
insert into orderCombine values('1','1','1'); insert into orderCombine values('2','2','2'); insert into vipform values('1','5'); insert into vipform values('2','4'); insert into vipform values('1','2');

CREATE OR REPLACE TRIGGER "FG123"."TER_OV"
BEFORE
DELETE ON "ORDERCOMBINE" FOR EACH ROW 
BEGIN
DELETE   FROM   VIPForm 
WHERE   VIPForm.V_Id=:OLD.FormerId;
END;

DELETE FROM "FG123"."ORDERCOMBINE" 
WHERE FormerId ='1'

DELETE FROM "FG123"."ORDERCOMBINE" 
WHERE VIPForm ='1'；
DELETE FROM "FG123"."ORDERCOMBINE" 
WHERE FormerId ='1'