AttachDBFilename Property

SqlConnectionStringBuilder.AttachDBFilename Property


Gets or sets a string that contains the name of the primary data file. This includes the full path name of an attachable database.

Namespace:   System.Data.SqlClient
Assembly:  System.Data (in System.Data.dll)

public string AttachDBFilename { get; set; }

Property Value

Type: System.String

The value of the AttachDBFilename property, or String.Empty if no value has been supplied.

Exception Condition

To set the value to null, use Value.

This property corresponds to the "AttachDBFilename", "extended properties", and "initial file name" keys within the connection string.

AttachDBFilename is only supported for primary data files with an .mdf extension.

An error will be generated if a log file exists in the same directory as the data file and the 'database' keyword is used when attaching the primary data file. In this case, remove the log file. Once the database is attached, a new log file will be automatically generated based on the physical path.

The following example creates a new SqlConnectionStringBuilder instance, and sets the AttachDBFilename property in order to specify the name of an attached data file.

using System.Data.SqlClient;

class Program
    static void Main()
            string connectString =
                "Server=(local);" +
                "Integrated Security=true";
            SqlConnectionStringBuilder builder =
                new SqlConnectionStringBuilder(connectString);
            Console.WriteLine("Original: " + builder.ConnectionString);
            Console.WriteLine("AttachDBFileName={0}", builder.AttachDBFilename);

            builder.AttachDBFilename = @"C:\MyDatabase.mdf";
            Console.WriteLine("Modified: " + builder.ConnectionString);

            using (SqlConnection connection = new SqlConnection(builder.ConnectionString))
                // Now use the open connection.
                Console.WriteLine("Database = " + connection.Database);
            Console.WriteLine("Press any key to finish.");
        catch (Exception ex)

.NET Framework
Available since 2.0
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