Cross database queries - a survey of sorts

I'm creating a database system in SQL Server 2000 but don't want to be stuck if my employer want to use another RDBMS in the future.

In SQL Server, it is possible to run a query against a database from another database. For example:

use DataBaseA
go
select * from DataBaseA.dbo.tableA
go

Is this common in other relational databases? What kind of syntax is involved?

Also, SQL Server has what I assume is a proprietary method for inserting a record in a table with an auto-incrementing (identity) field, and then returning the newly created number. How do other database systems handle this?

Thanks in advance. Received on Mon Sep 23 2002 - 18:12:34 CDT