I have been fortunate enough to work with a lot of data which involve using of PowerPivot or customers using Tabular model using BISM. Though there are striking similarities in building both the tasks, the mistakes made in both these models are almost the same. Let me talk you through this for a moment.
Whenever we work with PowerPivot or BISM model and we are importing data from a data source, the initial tendency is to use the “From Database” or “From Other Sources” tab and we start building the model. This is a fair step and in doing a data mashup, we bring data from multiple sources.
Many a times we might connect to the same data source using the above step. And to our irony we will encounter the following in our existing connections. In the example below, I have made 3 different query to the same data source and it is now pointing to the same source – 3 times. Isn’t it inefficient? I have seen customers having close to 20-25 connections to the same source but they are bringing some 20-25 different tables. I have observed the performance during “refresh” gets severely hampered by this approach.
So how to get around this? The steps are simple. Whenever you want to connect to the same source – click on the “Existing Connections” button.
Select the source that you want to reuse as a connection. And now select “Open”.
We will be presented with the same wizard as we normally do with “New Connection” Wizard.
The steps are similar when using the same in Visual Studio too when developing BISM models.