Is it possible to run an application built on sql

Question

I have a .NET 4.0, SQL Server 2008 application built on VS 2010.

Since more than 10 months I have been working on a project and its completed now. I moved to the next task of creating an installation of the software. Its also done. But now I have a big issue.

My clients already run software running SQL Server 2005 and its installed on their system. However when I was packaging my VS2010 C# application, I deployed it with prerequisite of SQL Server 2008 but now the problem is, when I try to install my application, it asks to uninstall the 2005 and then to install 2008. But my clients are very rigid to allow my program to uninstall any application on their system. I am stuck here.

I also tried to remove it from my prerequisites and the application was successful to install itself but after when I tried to run my application, its unable to access the database.

How I can solve this issue? Is there any way to make application and database both work with SQL Server 2005 or 2008. Or maybe any other expert advice.

EDIT 1

I also have Datetime stuff which really annoyed with to accomplish, as my project is multilingual so I have separate functions to handle datetime to insert in SQL.

EDIT 2

Is it possible to upgrade SQL Server 2005 to 2008 using my own Visual Studio Deployment Project?

EDIT 3

This is the error I am getting

Prerequisite check for system component SQL Server 2008 Express failed with the following error message:
SQL Server 2008 Express Service Pack 1 (x64) cannot upgrade the existing instance of SQL Server 2005 Express (x64 WoW) named 'SQLEXPRESS'. Uninstall this instance of SQL Server 2005 Express and retry installing SQL Server 2008 Express Service Pack 1 (x64)."

See the setup log file located at 'C:\Users\BOOGI~1\AppData\Local\Temp\VSD41A1.tmp\install.log' for more information.

EDIT 4 (Main)

Is it possible to make a Microsoft SQL Server database file compatible to run with both SQL Server 2005 and SQL Server 2008?

Answer 1

It is usually not a problem to run an application against any version of SQL Server. Create the database using Management Studio and you're ready to go.

If you have a setup, you may need to change the prerequisites, so that it works with SQL Server 2005.

You may have to adjust the connection string. In the error message you're providing, it is obvious that the instance name of the SQL Server is "SQLEXPRESS", so you need to add this in your connection string.

Also, it is not a problem to run SQL 2005 Express and 2008 Express side by side.

Answer 2

One thing you can do is install SQL 2005 in your development machine or another machine then migrate your schema's and data from SQL Server 2008 to SQL Server 2005 and get your C# application working again. .NET 4.0 doesn't care which version of SQL server you are connecting to as long as you have the appropriate drivers installed for each appropriate database.

For your datetime create a function in SQL server so that it works in both version. Check out some examples in this link.

Thanks, Kalagen