LightSwitch and Self-Service BI
Visual Studio LightSwitch has been on my list of Things To Check Out When I Have Time for a while now; my upcoming session on the uses of OData feeds for BI at the PASS BA Conference (which will be a lot more exciting than it sounds – lots of cool demos – please come!) has forced me to sit down and take a proper look at it. I have to say I’ve been very impressed with it. It makes it very, very easy for people with limited coding skills like me to create data-driven line-of-business applications, the kind that are traditionally built with Access. Check out Beth Massi’s excellent series of blog posts for a good introduction to how it works.
How does LightSwitch relate to self-service BI though? The key thing here is that aside from its application-building functionality, LightSwitch 2012 automatically publishes all the data you pull into it as OData feeds; it also allows you to create parameterisable queries on that data, which are also automatically published as OData. Moreover, you can publish a LightSwitch app that does only this – it has no UI, it just acts as an OData service.
This is important for self-service BI in two ways:
- First of all, when you’re a developer building an app and need to provide some kind of reporting functionality, letting your end users connect direct to the underlying database can cause all kinds of problems. For example, if you have application level security, this will be bypassed if all reporting is done from the underlying database; it makes much more sense for the reporting data to come from the app itself, and LightSwitch of course does this out of the box with its OData feeds. I came across a great post by Paul van Bladel the other day that sums up these arguments much better than I ever could, so I suggest you check it out.
- Secondly, as a BI Pro setting up a self-service BI environment, you have to solve the problem of managing the supply of data to your end users. For example, you have a PowerPivot user that needs sales data aggregated to the day level, but only for the most recent week, plus a few other dimension tables to with it, but who can’t write the necessary SQL themselves. You could write the SQL for them but once that SQL is embedded in PowerPivot it becomes very difficult to maintain – you would want to keep as much of the complexity out of PowerPivot as possible. You could set up something in the source database – maybe a series of views – that acts as a data supply layer for your end users. But what if you don’t have sufficient permissions on the source database to go in and create the objects you need? What if your source data isn’t actually in a database, but consists of other data feeds (not very likely today, I concede, but it might be in the future)? What if you’re leaving the project and need to set up a data supply layer that can be administered by some only-slightly-more-technical-than-the-rest power user? LightSwitch has an important role to play here too I think: it makes it very extremely easy to create feeds for specific reporting scenarios, and to apply security to those feeds, without any specialist database, .NET coding or SQL knowledge.
These are just thoughts at this stage – as I said, I’m going to do some demos of this in my session at the PASS BA Conference, and I’ll turn these demos into blog posts after that. I haven’t used LightSwitch as a data provisioning layer in the real world, and if I ever do I’m sure that will spur me into writing about it too. In the meantime, I’d be interested in hearing your feedback on this…