Postgresql存储过程中基于会话的全局变量? [英] Session based global variable in Postgresql stored procedure?

问题描述

在Oracle的PL/SQL中，我可以使用包定义创建基于会话的全局变量.使用Postgresql的PLpg/SQL，似乎不可能，因为没有包，只有独立的过程和函数.

In Oracle's PL/SQL I can create a session based global variable with the package definition. With Postgresql's PLpg/SQL, it doesn't seem possible since there are no packages, only independent procedures and functions.

这是PL/SQL将g_spool_key声明为全局变量的语法...

Here is the syntax for PL/SQL to declare g_spool_key as a global...

CREATE OR REPLACE PACKAGE tox IS
        g_spool_key spool.key%TYPE := NULL;
        TYPE t_spool IS REF CURSOR RETURN spool%ROWTYPE;
        PROCEDURE begin_spool;
        PROCEDURE into_spool
            (
            in_txt IN spool.txt%TYPE
            );
        PROCEDURE reset_spool;
        FUNCTION end_spool
            RETURN t_spool;
        FUNCTION timestamp
            RETURN VARCHAR2;
    END tox;

如何使用PLpg/SQL实现基于会话的全局变量?

How would I implement a session based global variable with PLpg/SQL?

推荐答案

您可以在postgresql.conf中定义一些自定义变量类，并将其用作存储过程中的连接变量.参见文档.

You could define some custom-variable-classes in your postgresql.conf and use it as connection-variables in your stored-procedure. See the docs.

自定义变量类"imos"的用法示例:

Usage example for a custom-variable-class "imos":

imos=> set imos.testvar to 'foobar';
SET
Time: 0.379 ms
imos=> show imos.testvar;
 imos.testvar
--------------
 foobar
(1 row)

Time: 0.333 ms
imos=> set imos.testvar to 'bazbar';
SET
Time: 0.144 ms
imos=> show imos.testvar;
 imos.testvar
--------------
 bazbar
(1 row)

在存储过程中，您可以使用内置函数 current_setting( 'imos.testvar').

In stored-procedures you can use the built-in function current_setting('imos.testvar').

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