Hi Everyone,

I have several .NET applications which are to be migrated to Azure. These applications have different databases. However, there are scenarios where we use cross database queries in the applications.

We are migrating the DBs in to azure SQL. But, major issue with that approach is SQL Azure DB doesnt support cross database queries.

My question is by using elastic scale can we achieve this functionality?

Can we perform cross database queries with elastic scale where the dbs are having different schemas?

Many thanks for your question. The easiest way that I see to accomplish cross-database queries for your vertical partitioning scenario is to use Elastic Database Queries - a new feature in Azure SQL DB currently in preview. With the current Elastic Query functionality, you define a separate Elastic Scale shard map for each database that you want to access remotely. You then create Elastic Query external data sources and external tables pointing to these shard maps in those database where you want to issue the remote queries from. Creating these separate shard maps is a bit cumbersome and we are working on functionality to make this much simpler. However, the approach outlined before will give you the ability to query across databases with current SQL DB functionality (within the limitations of Elastic Query that are outlined in our documentation).

The best entry points into the Elastic Query feature are the following documents:

Elastic Database Query overview: https://azure.microsoft.com/en-us/documentation/articles/sql-database-elastic-query-overview/

Elastic Database Query step-by-step tutorial: https://azure.microsoft.com/en-us/documentation/articles/sql-database-elastic-query-getting-started/

Please keep me posted on how this works out for you. Also, if you hit any issues or have further questions, please contact me at torsteng (at) microsoft (dot) com.

Thanks,

Torsten