Setting up Business Connectivity Services in SharePoint 2010

The Business Connectivity Services (BCS) are a set of services which are used to connect to external data such as a SQL Server database. In combination with SharePoint designer, it is fairly easy to create external content types and lists (creating it in Visual Studio is also a possibility but more difficult to do). Personally, I had a little bit of difficulty setting it up the whole thing. The first thing I tried to do was to create an external content type for an arbitrary table in SQL Server, but I got the following error in SharePoint Designer: "The Business Data Connectivity Metadata Store is currently unavailable."

Other SP peers seemed to have the same problem and many could solve it by installing a WCF hotfix (KB976462), however this did not work for me. I will show you three checks I did in order to have stuff working. 1. Check if the Business Data Connectivity Service is running. You can find it by going to "Central Administration" -> "Manage services on server". If it has stopped, start it again.

2. Make sure you've got a Business Data Connectivity Service Application set up in "Application Management" ->"Service Applications"->"Manage service applications"

3. The next one is what I overlooked and made me waste hours of my life. Go to "Application Management"->"Service Applications"->"Configure service applications associations". In here you need to check whether your BCS Application Proxy is checked, otherwise it won't work.