From S132999:

"I have implemented this suggestion in 12.2. Starting with this version you can use an optional
'-connectionString' parameter followed with a custom connection string that will be used by the DBUpdater instead of the ones specific in the application configuration file or application itself.

Here is an example of how to use the new parameter:

D:\2012.2\XAF\Demos\CS\MainDemo\MainDemo.Win\bin\Debug>DBUpdater.v12.2.exe MainD
emo.Win.exe.config -connectionString "Integrated Security=SSPI;Pooling=false;Dat
a Source=.\SQLEXPRESS;Initial Catalog=Test""