Question

In my project I am filling two database tables with two DataSets. The method which I am using to fill those database tables is shown below:

SqlCommand sqlCommand = new SqlCommand();            
SqlCommand command;
using (SqlConnection conn = new SqlConnection(strConn))
{
    using (SqlCommand cmd = new SqlCommand(strQuery, conn))
    {
        using (SqlCommand cmdReset = new SqlCommand("DBCC CHECKIDENT('Doctor', RESEED, 0)", conn))
        {
            using (SqlCommand cmdUnCheck = new SqlCommand("alter table [dbo].[Doctor] nocheck constraint all",conn))
            {
                using (SqlCommand cmdCheck = new SqlCommand("alter table [dbo].[Doctor] with check check constraint all",conn))
                {
                    SqlDataAdapter da = new SqlDataAdapter(cmd);
                    conn.Open();
                    SqlTransaction sqlTransaction = conn.BeginTransaction();
                    cmd.Transaction = sqlTransaction;
                    cmdReset.Transaction = sqlTransaction;
                    cmdUnCheck.Transaction = sqlTransaction;
                    cmdCheck.Transaction = sqlTransaction;
                    try
                    {
                        cmdUnCheck.ExecuteNonQuery();
           /*ERROR*/    cmd.ExecuteNonQuery();
                        cmdReset.ExecuteNonQuery();//deleting database table data
                        foreach (DataRow dr in ds.Tables[0].Rows) //Inserting new data into the Database table
                        {
                            command = new SqlCommand(query.createDoctorRow("Doctor",
                            dr[1].ToString(), dr[2].ToString(), Convert.ToInt64(dr[3]), Convert.ToInt32(dr[4])), conn, sqlTransaction);
                            command.ExecuteNonQuery();
                        }
                        cmdCheck.ExecuteNonQuery();
                        sqlTransaction.Commit();
                        conn.Close();
                    }
                    catch (Exception e)
                    {
                        sqlTransaction.Rollback();
                        throw;
                    }
                }
            }
        }
    }                
}

The above code was working fine till the second Database table was empty but when I inserted some data in it and then run the code, VS is showing error –>

The DELETE statement conflicted with the REFERENCE constraint “FK_Dr_ID”. The conflict occurred in database “Hospital”, table “dbo.Patient”, column ‘Doctor_ID’.
The statement has been terminated.

This seems clear that the foreign key is restricting the query to take place but as I am a beginner and dont know what to do I am asking your help..

In the above code I made changes referring to this SO answer but no joy, the error still exists at the same point.

Optional: Is there anyway to reduce the using statements in my code?

Answer 1

You can’t delete the data in the DOCTOR table since you have a relation to the Patient table via the Id of the DOCTOR.