SSRS Report Data Source for Query with Multiple Databases

Question

I have a dataset that pulls from multiple databases on the same server. Historically (without doing research) in this case I would set the data source to ReportServer (the database that houses the execution log for the server, ect.) and noticed the dataset doesn't seem to care what the data source is.

I did a few hours of digging and couldn't find an answer. When using (or in my case, unioning) multiple data bases in a dataset, what should the dataset data source be in Visual Studio?

Answer 1

Specifying the database in the connection string sets the starting, default database for the query. If your permissions are adequate, then there is nothing to stop you from accessing other databases.

The database in the connection string will give your query the context that is used when you don't specify a database name as part of a table. If your query is simply:

SELECT * FROM vw_Interactions

then this will run against the database specified in your connection string.

For your case, when using a table with the same name across multiple databases, the default database doesn't matter much, as long as the data access account has permissions that let the query work.