PostgreSQL自定义异常？ [英] PostgreSQL custom exceptions?

问题描述

在Firebird中，我们可以声明自定义异常：

In Firebird we can declare custom exceptions like so:

CREATE EXCEPTION EXP_CUSTOM_0异常：自定义异常;

CREATE EXCEPTION EXP_CUSTOM_0 'Exception: Custom exception';

这些都存储在数据库级。在存储过程中，我们可以像这样引发异常：

these are stored at the database level. In stored procedures, we can raise the exception like so:

EXCEPTION EXP_CUSTOM_0;

EXCEPTION EXP_CUSTOM_0 ;

PostgreSQL中有一个等价物吗？

Is there an equivalent in PostgreSQL ?

推荐答案

不，不是这样。但是你可以提高和维护自己的例外，没有问题：

No, not like this. But you can raise and maintain your own exceptions, no problem:

CREATE TABLE exceptions(
    id serial primary key,
    MESSAGE text, 
    DETAIL text, 
    HINT text, 
    ERRCODE text
);

INSERT INTO exceptions (message, detail, hint, errcode) VALUES ('wrong', 'really wrong!', 'fix this problem', 'P0000');

CREATE OR REPLACE FUNCTION foo() RETURNS int LANGUAGE plpgsql AS
$$
DECLARE
    row record;
BEGIN
    PERFORM * FROM fox; -- does not exist, undefined_table, fail

    EXCEPTION
        WHEN undefined_table THEN
            SELECT * INTO row FROM exceptions WHERE id = 1; -- get your exception
            RAISE EXCEPTION USING MESSAGE = row.message, DETAIL = row.detail, HINT = row.hint, ERRCODE = row.errcode;

    RETURN 1;
END;
$$

SELECT foo();

您也可以在您的程序中使用硬编码，这取决于您。

Offcourse you can also have them hardcoded in your procedures, that's up to you.

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