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_form foreign key(V_id)   references   orderbine(formerid) );  
insert into orderCombine values('1','1','1'); insert into orderCombine values('2','2','2'); insert into form values('1','5'); insert into form values('2','4'); insert into form 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'