.NET - SQL Connection Error - Developing a Web App Locally

Question

I have Visual Studio 2008 and SQL Server 2008 Developer Edition installed on a Windows XP machine.

I get this error when trying to work on a Test Web Application:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

My ADO.NET connection string is:

Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\TestDB.mdf;Integrated Security=True;User Instance=True

Shouldn't a full install of SQL Server know how to handle SQL Express databases? Am I missing an install of something I need to work on an "attached" database? or do I still need to configure something? I think this has just worked for me (out-of-the-box) in the past.

update:
My intention is to use this as an Express DB even though I have a full-blown 2008 instance running. Can't you do this? Doesn't ASP.NET steer you towards one of these "express" databases by default when you try to use its Membership functionality?

Answer 1

What version of SQl server did you install? That connection string is for the express edition and will not work for the other editions

see here for connection strings http://www.connectionstrings.com/

Answer 2

Your SQL Server Developer edition doesn't use "SQLExpress" as the server name/instance - try using your server name or (local) instead.

Also, your string is inappropriate for an already-attached database. The string should look something like this:

connectionString="Data Source=(local);Initial Catalog=YourDatabaseName;IntegratedSecurity=True"

Update: ASP.NET won't steer you toward any particular database. In every way that really matters, all that ASP.NET cares about is that your connection string results fully and accurately describes the path and credentials needed to access some instance of SQL Server. Have you thought about trying out a more traditional connection string and then backing off one item at a time (e.g. naming the database file only after you've verified that the "normal" database connection runs correctly)?

Answer 3

Open up the SQL Server Management Studio

Look at the connection info it puts out when you log in.

Use that value in your connection string.

Make sure you have SQL Configuration to allow for connections.

One last thing to look at if the previous two steps don't help is to look at the firewall settings.