SQLite - 如何连接来自不同数据库的表？ [英] SQLite - How do you join tables from different databases?

问题描述

我有一个使用SQLite数据库的应用程序，一切都按照它应该的方式工作。我现在正在添加需要第二个SQLite数据库的新功能，但我很难找到如何从不同的数据库连接表。

<

编辑：请参阅这个问题一个例子你可以适应你的语言，当你附加数据库如上所述

您可以使用将附加的另一个数据库文件附加到当前连接。 /sqlite.org/lang_attach.htmlrel =nofollow noreferrer> ATTACH 关键字。

  attach'database1 .db'as db1; 
 attach'database2.db'as db2; 
  

您可以使用关键字

查看所有连接的数据库

  .databases 
  

那么你应该能够

  select 
 * 
从
 db1.SomeTable a 
 inner join 
 db2.SomeTable b on b.SomeColumn = a.SomeColumn; 
  

请注意，数据库名称 main 和 temp 保留用于主数据库和数据库保存临时表和其他临时数据对象。这两个数据库名称对每个数据库连接都存在，不应使用附件。

I have an application that uses a SQLite database and everything works the way it should. I'm now in the process of adding new functionalities that require a second SQLite database, but I'm having a hard time figuring out how to join tables from the different databases.

If someone can help me out with this one, I'd really appreciate it!

Edit: See this question for an example case you can adapt to your language when you attach databases as mentioned in the accepted answer.

解决方案

You can attach another database file to the current connection using the ATTACH keyword.

attach 'database1.db' as db1;
attach 'database2.db' as db2;

You can see all connected databases with keyword

.databases

Then you should be able to do the following.

select
  *
from
  db1.SomeTable a
    inner join 
  db2.SomeTable b on b.SomeColumn = a.SomeColumn;

Note that "[t]he database names main and temp are reserved for the primary database and database to hold temporary tables and other temporary data objects. Both of these database names exist for every database connection and should not be used for attachment".

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