Dropping SQL Server database through C#

Question

I am using this code to delete a database through C#

Int32 result = 0;

try
{
        String Connectionstring = CCMMUtility.CreateConnectionString(false, txt_DbDataSource.Text, "master", "sa", "happytimes", 1000);

        SqlConnection con = new SqlConnection();
        con.ConnectionString = Connectionstring;

        String sqlCommandText = "DROP DATABASE [" + DbName + "]";
        if (con.State == ConnectionState.Closed)
        {
            con.Open();
            SqlConnection.ClearPool(con);
            con.ChangeDatabase("master");
            SqlCommand sqlCommand = new SqlCommand(sqlCommandText, con);
            sqlCommand.ExecuteNonQuery();
        }
        else
        {
            con.ChangeDatabase("master");
            SqlCommand sqlCommand = new SqlCommand(sqlCommandText, con);
            sqlCommand.ExecuteNonQuery();
        }



        con.Close();
        con.Dispose();
        result = 1;
    }
    catch (Exception ex)
    {
        result = 0;
    }
    return result;

But I get an error

Database currently in use

Can anyone help?

Answer 1

Try this:

String sqlCommandText = @"
ALTER DATABASE " + DbName + @" SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
DROP DATABASE [" + DbName + "]";

Also make sure that your connection string defaults you to the master database, or any other database other than the one you're dropping!

As an aside, you really don't need all of that stuff around your queries. The ConnectionState will always start off Closed, so you don't need to check for that. Likewise, wrapping your connection in a using block eliminates the need to explicitly close or dispose the connection. All you really need to do is:

String Connectionstring = CCMMUtility.CreateConnectionString(false, txt_DbDataSource.Text, "master", "sa", "happytimes", 1000);

using(SqlConnection con = new SqlConnection(Connectionstring)) {
    con.Open();
    String sqlCommandText = @"
        ALTER DATABASE " + DbName + @" SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
        DROP DATABASE [" + DbName + "]";
    SqlCommand sqlCommand = new SqlCommand(sqlCommandText, con);
    sqlCommand.ExecuteNonQuery();
}
result = 1;

Answer 2

Here is how you do it using Entity Framework version 6

System.Data.Entity.Database.Delete(connectionString);

Answer 3

You should take a look at SMO. These allow you to manage all aspects of SQL Server from code, including deleting of databases.

The database object has a Drop method to delete database.