PostgreSQL删除触发器

Question

我在PGAdminIII上创建了一个触发器,我想删除在另一个表上有外键的行.但是我收到一个语法错误,我找不到问题所在:

CREATE TRIGGER clienteDelete
BEFORE DELETE ON cliente
FOR EACH ROW
BEGIN
    DELETE FROM contacto WHERE contacto.id = OLD.contacto_idcontacto;
END;

ERROR:  syntax error at or near "BEGIN"
LINE 4: BEGIN
        ^

********** Error **********

ERROR: syntax error at or near "BEGIN"
SQL state: 42601
Character: 68

我不习惯Postgres上的触发器语法,但这是我根据SQL标准所知道的.任何帮助都会得到很高的评价

Answer 1

例如,Postgresql触发器有一些限制

PostgreSQL只允许为触发的动作执行用户定义的函数.

因此,要完成您想要的任务,您需要定义一个函数并使触发器触发.这样的事情应该有效:

CREATE FUNCTION clienteDelete() RETURNS TRIGGER AS $_$
BEGIN
    DELETE FROM contacto WHERE contacto.id = OLD.contacto_idcontacto;
    RETURN OLD;
END $_$ LANGUAGE 'plpgsql';

触发器:

CREATE TRIGGER delete_contacto 
BEFORE DELETE ON cliente 
FOR EACH ROW 
EXECUTE PROCEDURE clienteDelete();

我不是Postgresql专家,但是期待上面的代码不完美.