Oracle SQL - 触发器插入 table 从序列中传递空值

Question

我有两个table、TABLE_A和TABLE_B。当某些东西被插入 TABLE_A 时，有一个触发器也会将数据插入 TABLE_B。 TABLE_A 有一个使用序列填充的 ID 列。然后这个id也被插入到TABLE_B中。这是整个 DDL：

CREATE TABLE  "TABLE_A" 
   (    "ID" NUMBER(8,0) NOT NULL ENABLE, 
    "COLUMN1" NUMBER(8,0) NOT NULL ENABLE, 
    "COLUMN2" NUMBER(4,0) NOT NULL ENABLE
   )
/

CREATE TABLE  "TABLE_B" 
   (    "ID" NUMBER(8,0) NOT NULL ENABLE, 
    "COLUMN1" NUMBER(8,0) NOT NULL ENABLE, 
    "COLUMN2" NUMBER(4,0) NOT NULL ENABLE
   )

/   

  CREATE UNIQUE INDEX  "AID_PK" ON  "TABLE_A" ("ID")
/

ALTER TABLE  "TABLE_A" ADD CONSTRAINT "AID_PK" PRIMARY KEY ("ID")
  USING INDEX  "AID_PK"  ENABLE
/


create or replace TRIGGER my_trigger
BEFORE INSERT OR UPDATE OR DELETE ON TABLE_A
FOR EACH ROW
BEGIN
IF INSERTING THEN
INSERT INTO TABLE_B(
ID,
COLUMN1,
COLUMN2)
VALUES(
:new.ID,
:new.COLUMN1,
:new.COLUMN2);
END IF;
END;

/
ALTER TRIGGER  "my_trigger" ENABLE
/

 CREATE SEQUENCE   "MY_SEQ"  MINVALUE 1 MAXVALUE 999999999999999 INCREMENT BY 1 START WITH 5002 CACHE 20 NOORDER  NOCYCLE  NOKEEP  NOSCALE  GLOBAL;


/

CREATE OR REPLACE EDITIONABLE TRIGGER  "MYSEQ_SEQ_IOT" 
before insert on table_a
for each row
begin
select MY_SEQ.nextval into :new.id from dual;
end;

/
ALTER TRIGGER  "MYSEQ_SEQ_IOT" ENABLE
/

现在当我运行这条语句时：

INSERT INTO PER_ART(
    COLUMN1,
    COLUMN2
    )
VALUES(
    1111111,
    2222222);

我收到这个错误：

ORA-01400: cannot insert NULL into ("TABLE_B"."ID")
ORA-06512: at "my_trigger", line 7
ORA-04088: error during execution of trigger 'my_trigger'

为什么应该填充序列时 ID 为空？

Answer 1

你的两个触发器触发的顺序是不确定的。在我看来，最好的解决方案是只使用一个触发器：

create or replace TRIGGER my_trigger
  BEFORE INSERT ON TABLE_A
  FOR EACH ROW
BEGIN
  select MY_SEQ.nextval
    into :new.id 
    from dual;

  INSERT INTO TABLE_B(
    ID,
    COLUMN1,
    COLUMN2)
  VALUES(
    :new.ID,    -- Or use MY_SEQ.curreval
    :new.COLUMN1,
    :new.COLUMN2);
END;

如果出于某种原因必须有两个触发器，则可以使用 CREATE TRIGGER 语句的 FOLLOWS 和 PRECEDES 子句控制它们的触发顺序。有关控制触发顺序的详细信息，请参阅 the documentation。

Oracle SQL - 触发器插入 table 从序列中传递空值

Oracle SQL - Trigger inserting into table passing null value from sequence

sql

oracle

plsql

oracle12c