0 Row not found or changed

By Surendar N

0

Row not found or changed

Posted in

Row not found or changed


Recently I worked with linq. Linq makes the record insertion, deletion and update much easier in to a database. So I really found very easy in coding it.

The enjoyment not last for a day. Suddenly faced an error “Row not found or changed” while updating a record. But there is no problem with insertion or deletion.

Searched in all forums. People responded with

• Check if you have given the primary key for table
• Delete and recreate the dbml 

Did all those but didn’t work for me. I told to my colleague about this issue. Even he asked me if I did above 2 things. Then I showed the code. Below is my code which raised error.

void update(int _ID,String _Name,String _Age)
{
StudentTable _StudentTable = new StudentTable();
_StudentTable.ID=_ID;
_StudentTable.Name=_Name;
_StudentTable.Age=_Age;
using (DataContext dc = new DataContext(ConnectionString))
{
dc.StudentTables.InsertOnSubmit(_StudentTable);
dc.SubmitChanges();
}
}

And he simply laughed at me and told the basic about linq. That every record will have a unique indentifier other than primary key.  In my case ,used a TimeStamp so that it will avoid concurrency issue. Well so for the update he told me I should have first retrieved the record and changed the respective fields in it.

Below is the working code.

void update(int _ID,String _Name,String _Age)
{
StudentTable _StudentTable ;
connString = ConfigurationManager.ConnectionStrings["ConnectionString"].ToString();
using (DataContext dc =new DataContext(connString)
{
_ StudentTable = (from u in dc.StudentTables
where u.ID == ID
select u).FirstOrDefault();
}
_StudentTable.ID=_ID;
_StudentTable.Name=_Name;
_StudentTable.Age=_Age;
using (DataContext dc = new DataContext(ConnectionString))
{
dc.StudentTables.InsertOnSubmit(_StudentTable);
dc.SubmitChanges();
}
}

Really nice experience with linq.

Have a cheerful day