Alright, I found it, completely in visual studio. This can be from local (.mdf) files to server files and visa versa.
- Go to Sql Server Object Explorer and find your source database. Or in Server Explorer, right click on your source database and click on Browse in Sql Server Object Explorer
- When in Sql Server Object Explorer, right click on your source database and click on Data Comparison
- A dialog will popup, showing you a Source Database and Target Database. Your Source Database should already be selected. Now select your Target Database, you probably have to add a new connection, just do it like you would usually do in Server Explorer. If you want the target database to be a local (.mdf) file and you cannot click on Change, than add it first to the server explorer and it will popup in the combobox.
- Choose what you want to compare by checking the checkboxes and click next.
- It will connect to the servers and show you another dialog what to compare, check the checkboxes and click on Next.
- Here you will have an overview of your changes from source to target.
At this point, you will be able to kind of 'mirror' the source database with the target database. For instance: If you have added more records to the Target database then there are in the source database, then these records will be deleted once you click Update Target Take a close look at what will happen when you hit that button!
- If you are satisfied with the result, click Update Target. If you are not satisfied, next to the button there is a little icon to export it to a .sql file, so you can modify what will happen to the target database.
Unfortunately, after writing this, I found out that this is only available in VS Ultimate and Premium, that is what they say on the following link about visual studio 2010, I have tested this in Visual Studio 2015 Enterprise.
MSDN: https://msdn.microsoft.com/en-us/library/aa833428(v=vs.100).aspx