Re^2: how to use DBI connect to >1 database

Well done sir hippo- surprisingly, it WORKED! I used the $db1 handle which was connected to db1, and, remarkably, I can also read from tables in db2.. It seems counterintuitive since a DB handle connects to a specific database, yet it ALSO appears connected to others. It makes me wonder why I have to specify a database when making a connection?

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Re^3: how to use DBI connect to >1 database by ikegami (Patriarch) on Sep 28, 2023 at 17:24 UTC
yet it ALSO appears connected to others. No, it doesn't. You just connect to one server, and pass it the SQL to execute. It makes me wonder why I have to specify a database when making a connection? If you don't specify the server, how would it know to which server to connect and to send the SQL?	[reply]
Re^3: how to use DBI connect to >1 database by NERDVANA (Priest) on Sep 30, 2023 at 07:40 UTC
In some database engines you don't actually need to specify a database, since there's usually a default. But, if you did that you would need to specify fully qualified table names on every query, which would be annoying. Also, if you are a limited-access user sometimes the database wants you to choose so that it can make permission checks before allowing you to do anything. For a real mind-bender, Postgres has a feature where it can import views of foreign databases from other servers (or even types of server, like mysql!) and then you can run a single query across multiple database servers! It's a bit awkward to set up, though.	[reply]