Shulou(Shulou.com)05/31 Report--

This article mainly introduces how to use the trigger trigger in the database, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, let the editor take you to understand it.

The experiments are as follows:

Query the table DEPARTMENTS under the hr user to be defined by the trigger

SQL > conn hr/hr

Connected.

SQL > select * from tab

TNAME TABTYPE CLUSTERID

COUNTRIES TABLE

DEPARTMENTS TABLE

EMPLOYEES TABLE

EMP_DETAILS_VIEW VIEW

JOBS TABLE

JOB_HISTORY TABLE

LOCATIONS TABLE

REGIONS TABLE

8 rows selected.

-- create a trigger:

SQL > CREATE OR REPLACE TRIGGER tr_dept_time

2 BEFORE INSERT OR DELETE OR UPDATE

3 ON departments

4 BEGIN

5 IF (TO_CHAR (sysdate,'DAY') IN ('Saturday', 'Sunday') OR (TO_CHAR (sysdate,' HH24:MI') NOT BETWEEN'08 sysdate,'DAY' 30 'AND' 18 sysdate,'DAY' 00') THEN

6 RAISE_APPLICATION_ERROR (- 20001, 'not working hours, cannot modify departments table')

7 END IF

8 END

9 /

Trigger created.

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