检查 Postgres (plpgsql) 中是否存在序列 [英] Check if sequence exists in Postgres (plpgsql)

问题描述

我试图在一个存储过程中测试一个序列是否已经存在.

I'm trying to test, within a stored procedure, whether a sequence already exists.

IF EXISTS SEQUENCE seq_name
    RAISE EXCEPTION 'sequence % already exists!', seq_name
END IF;

我尝试了上面代码片段的几种变体，但都没有运气.我一定给 Google 提供了错误的术语，因为我似乎找不到有关该主题的任何内容.任何帮助表示赞赏！

I have tried several variations of the snippet above without luck. I must be giving Google the wrong terms because I can't seem to find anything on the topic. Any help is appreciated!

推荐答案

您应该可以查询 pg_class 表以查看 relname 是否存在.

You should be able query the pg_class table to see if the relname exists.

IF EXISTS (SELECT 0 FROM pg_class where relname = '<my sequence name here>' )
THEN
  --stuff here
END IF;

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