我正在尝试声明数据类型为record
的变量,但是在没有结果可填充时遇到麻烦。下面是该函数的简化模型:
CREATE OR REPLACE FUNCTION do_something()
RETURNS TRIGGER AS $$
DECLARE
engagement record;
BEGIN
SELECT code
INTO engagement
FROM "mainEngagement" me
WHERE me.value = NEW.id;
IF TG_OP = 'INSERT'
THEN
INSERT INTO engagement_details (code)
values (
case
when engagement is not null
then exists(select code from engagement where "value" = 'expected')
else false
end
);
ELSE
UPDATE engagement_details
SET
code = case
when engagement is not null
then exists(select 1 from engagement where "value" = 'expected')
else false
end
WHERE engagement_details.assessment_id = NEW.id;
END IF;
RAISE NOTICE 'Updated engagement_details: [%]', NEW;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
当触发器运行并且“ mainEngagement”中没有数据时,我在INSERT中遇到错误:
错误:关系“订婚”不存在
我找不到测试是否有人参与的方法。我搜索了很多堆栈溢出问题,但是大多数人只建议做engagement := row(null)
,但是when engagement is not null
仍然对我不起作用。
答案 0 :(得分:1)
使用IF NOT FOUND
:
SELECT code
INTO engagement
FROM "mainEngagement" me
WHERE me.value = NEW.id;
IF NOT FOUND
THEN
RAISE WARNING '|W| do_something(): engagement undefined'; -- report warning
RETURN; -- exit early, function cannot proceed
END IF;
答案 1 :(得分:0)
我在这里遇到的问题是,RECORD
条目只能有一行。我试图返回具有多个行的值,然后在记录上运行CASE
语句,但该语句永远无法工作。而是执行以下操作:
CREATE OR REPLACE FUNCTION do_something()
RETURNS TRIGGER AS $$
DECLARE
engagement boolean;
BEGIN
SELECT EXISTS (
SELECT 1 FROM engagement WHERE "value" = 'expected'
) INTO engagement;
IF TG_OP = 'INSERT'
THEN
INSERT INTO engagement_details (code)
values (engagement);
ELSE
UPDATE engagement_details
SET
code = engagement
WHERE engagement_details.assessment_id = NEW.id;
END IF;
RAISE NOTICE 'Updated engagement_details: [%]', NEW;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
更加简单,干净和有效。