PostgreSQL 过程语言“C"未找到 [英] PostgreSQL procedural language "C" not found

问题描述

我正在尝试在 PostgreSQL 9.2 数据库中使用 PL/R 过程语言.我已经安装了 plr 语言，我正在尝试将它添加到数据库中.当我运行命令 CREATE EXTENSION plr; 时，我收到以下错误:

I am trying to use the PL/R procedural language in a PostgreSQL 9.2 database. I have installed the plr language and I am trying to add it to a database. When I run the command CREATE EXTENSION plr; I get the following error:

ERROR:  language "C" does not exist
STATEMENT:  CREATE EXTENSION plr;
ERROR:  language "C" does not exist

当我使用 select * from pg_language; 列出数据库中的可用语言时，我得到

When I list the available languages in the database with select * from pg_language; I get

 lanname  | lanowner | lanispl | lanpltrusted | lanplcallfoid | laninline | lanvalidator | lanacl 
 ----------+----------+---------+--------------+---------------+-----------+--------------+--------
  internal |       10 | f       | f            |             0 |         0 |         2246 | 
  c        |       10 | f       | f            |             0 |         0 |         2247 | 
  sql      |       10 | f       | t            |             0 |         0 |         2248 | 
  plpgsql  |       10 | t       | t            |         12514 |     12515 |        12516 | 
 (4 rows)

所以有一种语言 c 但它不是大写字母(不确定这是否有区别).

So there is a language c but it is not in capital letters (not sure if that makes a difference).

我想知道为什么 plr 扩展找不到 C 过程语言?

I am wondering why the plr extension does not find the C procedural language?

推荐答案

您可能正在 PostgreSQL 9.2 中遇到此更改(引用 此处为发行说明):

You are probably running into this change in PostgreSQL 9.2 (quoting the release notes here):

不再在 CREATE 中强制小写程序语言名称功能(罗伯特·哈斯)

No longer forcibly lowercase procedural language names in CREATE FUNCTION (Robert Haas)

虽然未加引号的语言标识符仍然是小写的，但字符串和带引号的标识符不再被强制小写.因此例如CREATE FUNCTION ... LANGUAGE 'C' 将不再有效；一定是拼写为c"，或者最好省略引号.

While unquoted language identifiers are still lowercased, strings and quoted identifiers are no longer forcibly down-cased. Thus for example CREATE FUNCTION ... LANGUAGE 'C' will no longer work; it must be spelled 'c', or better omit the quotes.

这也反映在 CREATE FUNCTION<的手册中/code>

lang_name

实现函数的语言名称.可以是SQL、C、internal或用户名- 定义的程序语.为了向后兼容，名称可以用单引号.

The name of the language that the function is implemented in. Can be SQL, C, internal, or the name of a user-defined procedural language. For backward compatibility, the name can be enclosed by single quotes.

至少从 7.3 版(可能更长)开始，不鼓励引用语言名称，但显然旧习惯很难改掉.删除围绕 'C' 的引号可以解决问题，得到:LANGUAGE c 或 LANGUAGE C.

Quoting the language name has been discouraged since at least version 7.3 (maybe longer), but old habits die hard, obviously. Removing the quotes around 'C' fixes the problem, arriving at: LANGUAGE c or LANGUAGE C.

PL/R 在这方面还没有为 PostgreSQL 9.2 做好准备，从 项目页面.

PL/R wasn't ready for PostgreSQL 9.2 in that respect, judging from the project page.

Joe Conway 留下了一个被删除的答案，因为它应该是一条评论.我把它贴在这里给看不到已删除答案的普通大众:

Joe Conway left an answer that got deleted because it should be a comment. I paste it here for the general public who can't see deleted answers:

我收到消息，只是还没来得及发布新的 PL/R 版本.在 12 月之前寻找它，但同时手动解决方法上面提到的很简单.

I got the message, just haven't had the time to do a new PL/R release. Look for it by December, but in the meantime the manual workaround noted above is pretty simple.

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