什么是高级？这就叫高级—openGauss（312）

#openGauss #入门 #安装 #数据库 #开源

知识来源：docs-opengauss.osinfra.cn/zh/

示例

--创建源表及触发表
openGauss=# CREATE TABLE test_trigger_src_tbl(id1 INT, id2 INT, id3 INT);
openGauss=# CREATE TABLE test_trigger_des_tbl(id1 INT, id2 INT, id3 INT);

--创建触发器函数
openGauss=# CREATE OR REPLACE FUNCTION tri_insert_func() RETURNS TRIGGER AS
           $$
           DECLARE
           BEGIN
                   INSERT INTO test_trigger_des_tbl VALUES(NEW.id1, NEW.id2, NEW.id3);
                   RETURN NEW;
           END
           $$ LANGUAGE PLPGSQL;

openGauss=# CREATE OR REPLACE FUNCTION tri_update_func() RETURNS TRIGGER AS
           $$
           DECLARE
           BEGIN
                   UPDATE test_trigger_des_tbl SET id3 = NEW.id3 WHERE id1=OLD.id1;
                   RETURN OLD;
           END
           $$ LANGUAGE PLPGSQL;

openGauss=# CREATE OR REPLACE FUNCTION TRI_DELETE_FUNC() RETURNS TRIGGER AS
           $$
           DECLARE
           BEGIN
                   DELETE FROM test_trigger_des_tbl WHERE id1=OLD.id1;
                   RETURN OLD;
           END
           $$ LANGUAGE PLPGSQL;

--创建INSERT触发器
openGauss=# CREATE TRIGGER insert_trigger
           BEFORE INSERT ON test_trigger_src_tbl
           FOR EACH ROW
           EXECUTE PROCEDURE tri_insert_func();

--创建UPDATE触发器
openGauss=# CREATE TRIGGER update_trigger
           AFTER UPDATE ON test_trigger_src_tbl  
           FOR EACH ROW
           EXECUTE PROCEDURE tri_update_func();

--创建DELETE触发器
openGauss=# CREATE TRIGGER delete_trigger
           BEFORE DELETE ON test_trigger_src_tbl
           FOR EACH ROW
           EXECUTE PROCEDURE tri_delete_func();

--执行INSERT触发事件并检查触发结果
openGauss=# INSERT INTO test_trigger_src_tbl VALUES(100,200,300);
openGauss=# SELECT * FROM test_trigger_src_tbl;
openGauss=# SELECT * FROM test_trigger_des_tbl;  //查看触发操作是否生效。

--执行UPDATE触发事件并检查触发结果
openGauss=# UPDATE test_trigger_src_tbl SET id3=400 WHERE id1=100;
openGauss=# SELECT * FROM test_trigger_src_tbl;
openGauss=# SELECT * FROM test_trigger_des_tbl;  //查看触发操作是否生效

--执行DELETE触发事件并检查触发结果
openGauss=# DELETE FROM test_trigger_src_tbl WHERE id1=100;
openGauss=# SELECT * FROM test_trigger_src_tbl;
openGauss=# SELECT * FROM test_trigger_des_tbl;  //查看触发操作是否生效

--修改触发器
openGauss=# ALTER TRIGGER delete_trigger ON test_trigger_src_tbl RENAME TO delete_trigger_renamed;

--删除触发器
openGauss=# DROP TRIGGER insert_trigger ON test_trigger_src_tbl;
openGauss=# DROP TRIGGER update_trigger ON test_trigger_src_tbl;
openGauss=# DROP TRIGGER delete_trigger_renamed ON test_trigger_src_tbl;

#openGauss #入门 #安装 #数据库 #开源

知识来源：docs-opengauss.osinfra.cn/zh/