postgresql 如何捕获独立于使用的数据库/引擎的错误 1062“重复条目”？
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How to catch error 1062 "duplicate entry" independent from used database/engine?
提问by Florian
In a project I started out with MySQL as database. Instead of checking first, I just do an insert and if I get an IntegrityError exception with code 1062, I know that there is a duplicate entry and warn the user, to do this and that.
在一个项目中，我开始使用 MySQL 作为数据库。我没有先检查，而是执行插入操作，如果我收到代码为 1062 的 IntegrityError 异常，我知道存在重复条目并警告用户执行此操作。
that looks basically like this:
看起来基本上是这样的：
try:
# add duplicate, nothing bad happens yet, is only in sqla session
db.session.add(User(email='already_used_email@address_that_has_to_be_unique.com'))
# commit, now the IntegrityError is raised, when sqla inserts
db.session.commit()
except IntegrityError as e:
db.session.rollback()
# this is what i do with mysql, check the exception for code 1062
# how can i replace this with something db independent?
code, msg = e.orig
if code == 1062:
# send warning
pass
Now, for one this makes it already impossible to test with eg. in-memory sqlite. Not nice, but I could live with that.
现在，对于其中之一，已经无法使用例如进行测试。内存中的sqlite。不太好，但我可以忍受。
Second however, I might (have to/want to for other out of scope of this question issues) switch to Postgres. Of course I could just change the code to (also) check for Postgres error codes, but I was hoping there is a way to have SQLALchemy tell me, that a duplicate happened independent from the database. A database dialect abstraction...?
然而，其次，我可能（必须/想要解决此问题范围之外的其他问题）切换到 Postgres。当然，我可以将代码更改为（也）检查 Postgres 错误代码，但我希望有一种方法可以让 SQLALchemy 告诉我，重复发生独立于数据库。数据库方言抽象...？
采纳答案by Richard Huxton
What you want to search for is something called "SQLSTATE" - a set of standard error codes that cover most common RDBMS error states. They don't necessarily provide enough detail for all purposes though, and I don't know if sqlite supports them.
您要搜索的是称为“SQLSTATE”的东西——一组涵盖最常见 RDBMS 错误状态的标准错误代码。不过，它们不一定为所有目的提供足够的细节，我不知道 sqlite 是否支持它们。
