防止用触发器插入行

Question

如果使用触发器满足某一条件，则我试图防止插入行。我使用用户定义的异常来执行此操作，但是尽管抛出了异常，该行仍在插入。我不知道为什么会发生这种情况，我认为当异常被引发时，事务被回滚，不会插入任何内容。代码在下面。

create or replace TRIGGER 
  CHECK_OPTION
BEFORE INSERT 
ON lot_options  
FOR EACH ROW

DECLARE
    v_allowed_stage NUMBER;
    v_actual_completion_date DATE;
    option_change_invalid EXCEPTION;
BEGIN
    DBMS_OUTPUT.PUT_LINE('Starting the begin');
    SELECT stage_stage INTO v_allowed_stage
    FROM "TEAM3"."Option" o
    WHERE o.option_number = :new.option_number;
    DBMS_OUTPUT.PUT_LINE(v_allowed_stage);

    DBMS_OUTPUT.PUT('Stage in a cell');

    SELECT actual_completion INTO v_actual_completion_date
    FROM progress
    WHERE stage_stage = v_allowed_stage
    AND Lot_lot_number = :new.lot_lot_number;
    DBMS_OUTPUT.PUT_LINE('completion date in storage');


    IF (v_actual_completion_date IS NOT NULL)
    --DBMS_OUTPUT.PUT('condition holds true')
    THEN RAISE option_change_invalid;
    END IF;

    EXCEPTION
    WHEN option_change_invalid THEN
    DBMS_OUTPUT.PUT_LINE('Invalid Option Change: Option change is not allowed in this stage of progress.');
END;

Answer 1

删除异常块，以便不再捕获错误。然后，该错误将传播出去，并防止和防止插入发生。