Question

i have one column in my database by name PNUMSET (Primary Key) contains unique data.(approx 1L rows)

and in application i have one datatable with one column name NEWPNUM which contains data.

i want to check that no value is matching between existing database and current datatable values..

Note:- no of rows may or may not be same in database and datatable.

so far i tried…..

           String query = "Select PNUMSET FROM DUMMYTABLE";
           MySqlDataAdapter msda = new MySqlDataAdapter(query, connection);
           msda.Fill(dt);                

            for (int k = 0; k < Class1.global_dataset.Tables[0].Rows.Count; k++)
            {
                if (dt.Rows.Contains(Class1.global_dataset.Tables[0].Rows[k][4].ToString()))
                {
                    MessageBox.Show("Baj Gaya Ghanta!!!!");
                }
            }

Answer 1

You can use Linq-To-DataTable to join both tables on this column, for example:

var commonRows = from r1 in dt.AsEnumerable()
                 join r2 in Class1.global_dataset.Tables[0].AsEnumerable()
                 on r1.Field<int>(4) equals r2.Field<int>(4)
                 select r1;
if(commonRows.Any())
{
    // do something with these rows
}

(assuming the 5th column and it’s type int)

Note that although Enumerable.Join is quite efficient it might be better to compare this in the database instead of loading all into memory.