小编Chr*_* M.的帖子

使用 PostgreSQL 9.3 我一直在尝试定义一个assert辅助函数来检查空查询结果和类似的事情，如下所示：

CREATE FUNCTION public.assert (
    in_assertion boolean,
    in_errormessage text
)
RETURNS boolean
IMMUTABLE
LANGUAGE plpgsql
SECURITY INVOKER
AS $function$
    BEGIN
        IF NOT in_assertion THEN
            RAISE EXCEPTION 'assertion failed: %', in_errormessage;
        END IF;

        RETURN in_assertion;
    END;
$function$
;

经过测试，我发现异常没有像我期望的那样抛出。例如，对于CREATE TABLE emptytable (somecolumn text);和

CREATE FUNCTION public.testassert_buggy (
    out somevalue text
)
LANGUAGE sql
SECURITY DEFINER
AS $function$
    WITH firstquery AS (
            SELECT * FROM emptytable
    ), nonemptycheck AS (
            SELECT assert(count(*) = 42, 'nonemptycheck …