Question

我有一个带有表安全性的数据库和2个字段用户名和密码，其中包含几个我要删除的重复数据在C＃.net中复制我将使用的SQL语句是什么。在更新期间出现重复的用户名和密码来自另一个文件的数据库文件。或者如何仅复制数据库基本文件中不存在的记录。我需要在CSharp.net这里做它代码的一部分，我想删除数据。请帮助

        private void ReadUFbtn_Click(object sender, EventArgs e)
        {    //new data in desktop so it comes as Source so main becomes as backup
            // backup is main so here is mail pis in opened 
            string targetPath = @"C:\Users\User\Desktop\Prashant\";
            string constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\\PIS.mdb;Jet OLEDB:Database Password=Prashant;";
            Con = new OleDbConnection(@constr);
            Con.Open();
            Com = new OleDbCommand();
            Com.Connection = Con;

              try
              {
                  if (!System.IO.Directory.Exists(targetPath))
                  {
                      DialogResult X = MessageBox.Show("The Direcory / 5File Dose not exits", "PIS System");
                  }
                  else
                  {   
                      //backup open           
                      if (Con.State == ConnectionState.Closed)
                          Con.Open();
                          //target //main //backup              //source from data //desktop
                          //backup                                           // main data 
                      string selQuery = "INSERT INTO Security SELECT DISTINCT * FROM [MS Access;DATABASE=c:\\Users\\User\\Desktop\\Prashant\\PIS.mdb;PWD=Prashant;].[Security]";

                          Com.CommandText = selQuery;
                          Com.CommandType = CommandType.Text;
                          Com.Connection = Con;

                          MessageBox.Show("File Updated");
                          Com.CommandText = "SELECT DISTINCT * FROM Security  ";

                          int result = Com.ExecuteNonQuery();

                   }                     
                }
                catch(Exception ex) 
                    {
                        MessageBox.Show(ex.Message);
                    }
           }
    }
}

Answer 1

执行类似的操作应删除MS-Access中的重复记录

delete from Security 
where id not in
(select min(id) from Security T2
 where T2.username=Security.username and T2.password=Security.password)

我需要从MS访问中的数据库可编程性中删除重复数据

1 个答案: