Can SQL Server send a web request?

Question

I have an SQL Server database and an intranet web application on a local network. The intranet web application creates records and sends them to the database. I have an Inte

Answer 1

It is possible, but in the real world is a little bit more complicated than the naive approach you envision. Primarily, it is unacceptable to have a trigger wait for a HTTP request:

• For one, your application will crawl to a screeching halt, because triggers will block resources (primarily locks) waiting for a response from some far and away WWW service.
• Second, more subtle but far worse, is the issue of correctness in presence of rollbacks. If the transaction that issued to HTTP requests rolls back, there is no way to 'undo' the HTTP request.

The solution is to decouple the trigger from the HTTP request via a queue. The trigger enqueues the request into a local queue and commits, while a separate piece of processing dequeues these requests and issues the HTTP request. This solves both problems pointed out above. You can use ordinary tables for queues (see Using Tables as Queues) or you can use Service Broker, both work well.

Now on how to dequeue this requests and actually place the HTTP call, I strongly recommend using a dedicated process (ie. an application dedicated for this purpose). While it is possible to use SQLCLR, it is a very bad choice. SQL Server resources (specifically workers) are far to precious to waste on waiting for Internet responses.