postgresql触发器使用实例

发布时间：2020-12-13 17:28:29 所属栏目：百科来源：网络整理

导读：创建测试表： CREATE TABLE emp ( empname text NOT NULL, salary integer ); CREATE TABLE emp_audit( operation text NOT NULL, stamp timestamp NOT NULL, userid text NOT NULL, empname text NOT NULL, salary integer ); 创建存储过程： CREATE OR REPL

创建测试表：
CREATE TABLE emp (
empname text NOT NULL,
salary integer
);

CREATE TABLE emp_audit(
operation text NOT NULL,
stamp timestamp NOT NULL,
userid text NOT NULL,
empname text NOT NULL,
salary integer
);

创建存储过程：
CREATE OR REPLACE FUNCTION process_emp_audit()
RETURNS TRIGGER AS
$emp_audit$
BEGIN
IF (TG_OP = 'DELETE') THEN
INSERT INTO emp_audit SELECT 'DELETE',now(),user,OLD.*;
ELSIF (TG_OP = 'UPDATE') THEN
-- save old and new values
INSERT INTO emp_audit SELECT 'OLD',OLD.*;
INSERT INTO emp_audit SELECT 'NEW',NEW.*;
ELSIF (TG_OP = 'INSERT') THEN
INSERT INTO emp_audit SELECT 'INSERT',NEW.*;
ELSEIF (TG_OP = 'TRUNCATE') THEN
INSERT INTO emp_audit SELECT 'TRUNCATE','-',-1;
END IF;
RETURN NULL; -- result is ignored bacause this is an AFTER trigger
END;
$emp_audit$ LANGUAGE plpgsql;

创建针对insert和update每行的触发器：

CREATE TRIGGER emp_audit
AFTER INSERT OR UPDATE OR DELETE ON emp
FOR EACH ROW EXECUTE PROCEDURE process_emp_audit();

创建针对update的语句级的触发器：

CREATE TRIGGER emp_audit_truncate AFTER TRUNCATE ON emp FOR EACH STATEMENT EXECUTE PROCEDURE process_emp_audit();

（编辑：李大同）

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