I am developing an EF – MVC 3 application. I have used model first approach, so I have create model first and from that model, EF generated the DB.
I have used a tool called Nuget – Entity Generator – Database designer for generating the database. When I have designed the model first time, I have used the Generate Migration T-SQL and Deploy option of that tool.
Database generated perfectly and it’s working fine…
Now I have come across a situation that I have to make a change to the model and I have to use T-SQL Via T4 (TPH) option to update the database.

So previously I used different process to update DB and now I am changing it.
When I use the T-SQL Via T4 (TPH) all the tables get deleted and new tables get created.
How to avoid this ?
I want to only update the table which I have made the changes.
Entity framework 4.3 comes with migration support. This is not available in EF 4.1.
Some links from google:
http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-automatic-migrations-walkthrough.aspx
http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-code-based-migrations-walkthrough.aspx