>Hello Everybody.
>
>I have designed an application which is already fully functional on my system. I want to adjust it now to be able to make it a shrink wrap app.
>
>Currently that app is connecting to my MS SQL 2005 database. For it to be a shrink wrap the database connection should be flexible. Maybe the end customer already has SQL (any version) installed or maybe my app needs to install a light sql version, such as sql express or so.
>
>For this process I have a few questions:
>
>

Which light weight sql do you recommend?
>

Do I just need to change the connection string to the different database (given the table and fields are the same)?
>

Where do I change the connection string in the code? Or rather, should I have instead of the connection string a function call which returns the connection string?
>

How about username/password security? In my case here I am connection to a database which also has our enterprise data. I don't know if the password is encrypted and/or hidden - can someone get to it? How do I ensure this is save?
>

Any other thoughts concern to bring me on the right track?
>
>Thank you for all your great help!

If you want to play outside the MS sandbox then, obviously, switching connection strings isn't going to be enough.

Switching between SQL2000/2005/2008 and SQL Express shouldn't be an issue but building an install process that allows users to, for example, select an existing SQL instance or install a dedicated SQL Express server in a user-friendly way is not trivial.

As far a 'lightweight' goes - it depends on your app. If you can get by with CE then it greatly simplifies things. A 2Mb footprint instead of 200Mb. No installation beyond including a couple of .NET DLLs with your app. A few downsides though such as no support for SPROCs etc. Here's an (oldish) white paper comparing SQL Express to CE:http://download.microsoft.com/download/A/4/7/A47B7B0E-976D-4F49-B15D-F02ADE638EBE/Compact_Express_Comparison.doc