Question

I created a C# program that has a SQL Server database with Visual Studio 2010 and I created a setup program for this.

On my computer, when I install the program, it runs without any problems. However, when I install it on another computer, the program installs successfully, but the database of the program can’t run and the program has some problems with the database. I installed the .NET Framework 4 for this, but the problems hasn’t gone away.

What component (like .NET Framework 4) needs to be installed on another computer to run my program?

class db
{

    public string UserName="";
    public string Password="";

    private SqlConnection con;
    private SqlCommand cmd;
    private SqlDataAdapter da;

    public db()
    {
        con = new SqlConnection();
        cmd = new SqlCommand();
        da = new SqlDataAdapter();
        cmd.Connection = con;
        da.SelectCommand = cmd;
    }
    public void Connect()
    {
        string cs = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\my.mdf;Integrated Security=True;User Instance=True";


        con.ConnectionString = cs;
        con.Open();
    }

    public void Disconnect()
    {
        con.Close();
    }
    //Select Command
    public DataTable Select(string sql)
    {
        DataTable dt = new DataTable();
        cmd.CommandText = sql;
        da.Fill(dt);
        return dt;
    }

    //Insert , Update , Delete
    public void Docommand(string sql)
    {
        cmd.CommandText = sql;
        cmd.ExecuteNonQuery();
    }
}

Answer 1

The short answer is, your program needs exactly those components that you are using in your source code.

The .NET Framework 4 is available on most current Windows machines, so most likely, that is not the problem (but you might still want to make sure that your target machines do have .NET 4, and not just .NET 3.5.)

It’s more important to think about components that aren’t by default installed on the target machine. This includes, for example, SQL Server 2008. SQL Server, while from Microsoft, is a standalone product and not part of the .NET Framework. Even if you installed .NET 4, that wouldn’t just solve your database issues.

Unfortunately, you haven’t said whether you have a SQL Server or SQL Server Compact Edition database (the latter of which is only a file that can be deployed with your program, while the former is run as a system service on some server.)

In either case, make sure that every target machine can reach that database. This means:

• If it is a local SQL Server database (on the same machine where the application runs), SQL Server needs to be installed on every target machine. (We’re not talking about SQL Server CE here, but about the full-blown server product!)

• If it’s a database on a publicly reachable network server, make sure that you’ve got a valid connection string and that access rights are properly set up.

Update:

Let’s take a look at your connection string:

string cs = "Data Source=.\\SQLEXPRESS;AttachDbFilename=…\\my.mdf;…";

Judging from that, it appears that…

• You have installed SQL Server 2008 Express on your own machine, and you’ve created a database that is stored in a file my.mdf that resides in your program’s binary folder (e.g. bin/Release).

• You have set up your program so that it connects to the database by directly accessing the database file my.mdf.

Now, when you give your program to someone else, your program will do exactly the same as it does on your machine: It will try to open a database from the my.mdf database file in your program’s binary folder.

This process will fail on the target machine if any of these conditions is not met:

• SQL Server 2008 Express is not installed. Even if you access the database directly, SQL Server 2008 Express is still required for the database access to work.

• my.mdf does not get copied to your program’s output folder. You could easily check by opening your program’s solution, then switch to Solution Explorer, and look at the Properties of my.mdf. Is Copy to Output Folder set to Always or Copy if newer?

Without knowing your program’s exact purpose, I would advise you to take a look at SQL Server Compact Edition. Unlike SQL Server Express, the target user won’t have to install it; SQL Server Compact Edition is deployed to the target machine either as part of the .NET Framework, or (if not) as an additional assembly in your program’s binary folder. Instead of a .mdf file, your database will reside in a .sdf file, and certain database functionalities will be missing (probably advanced stuff like replication etc. that you typically wouldn’t need for a simple program anyway).