用SQL添加附加数据库

[C#]

   string mdf_file = this.textBox1.Text;  //mdf file's  path
   string log_file = this.textBox2.Text;  //log file's path
   string dbname = this.textBox3.Text; //database's name

   const string CONN_STRING ="Provider = SQLOLEDB;Data Source = (local);Initial Catalog = master;Trusted_Connection=Yes;";
   string sql ="";
   
   if(mdf_file!="")
   {
    if(log_file!="")
     sql = "use master "+
      " EXEC sp_attach_db @dbname = N'"+dbname+"',"+
      " @filename1 = N'"+mdf_file+"', "+
      " @filename2 = N'"+log_file+"'";
    else
     sql = "use master "+
      " EXEC sp_attach_db @dbname = N'"+dbname+"',"+
      " @filename1 = N'"+mdf_file+"'";
    System.Data.OleDb.OleDbConnection cn = new System.Data.OleDb.OleDbConnection(CONN_STRING);
    cn.Open();
    System.Data.OleDb.OleDbCommand cmd = cn.CreateCommand();
    cmd.CommandText = sql;
    cmd.ExecuteNonQuery();
    cn.Close();
    MessageBox.Show ("安装数据库成功完成！");
    Close();
   }
   else
   {
    MessageBox.Show ("请选择MDF文件[Log文件可选]！");
   }