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ODP.NET - Working with DataTableReader

ODP.NET - Working with DataTableReader

DataTableReader is complementary to a DataTable object, and is mainly used as a type of Data Reader in the disconnected mode. The following is the modified code: 

  1. 'create connection to db 
  2. Dim cn As New OracleConnection("Data Source=xe; _ 
  3.            User Id=scott;Password=tiger") 
  4.      Try 
  5.           Dim SQL As String 
  6.           'build the SELECT statement 
  7.           SQL = String.Format("SELECT ename, sal, job FROM emp 
  8.                     WHERE empno={0}", Me.txtEmpno.Text) 
  9.           'create the DataAdapter object 
  10.           Dim adp As New OracleDataAdapter(SQL, cn) 
  11.           'create the offline datatable 
  12.           Dim dt As New DataTable 
  13.           'fill the data table with rows 
  14.           adp.Fill(dt) 
  15.           'clear up the resources and work offline 
  16.           adp.Dispose() 
  17.           Dim dtr As DataTableReader = dt.CreateDataReader 
  18.           'check if it has any rows 
  19.           If dtr.HasRows Then 
  20.                'read the first row 
  21.                dtr.Read() 
  22.                'extract the details 
  23.                Me.txtEname.Text = dtr("ename") 
  24.                Me.txtSal.Text = dtr("sal") 
  25.                Me.txtJob.Text = dtr("job") 
  26.           Else 
  27.                'display message if no rows found 
  28.                MessageBox.Show("Not found") 
  29.           End If 
  30.      Catch ex As Exception 
  31.           'display if any error occurs 
  32.           MessageBox.Show("Error: " & ex.Message) 
  33.           'close the connection if it is still open 
  34.           If cn.State = ConnectionState.Open Then 
  35.                cn.Close() 
  36.           End If 
  37.      End Try 
  

You can observe the highlighted code, which creates a DataTableReader object by calling the CreateDataReader method related to the DataTable object. Once the DataTableReader is created, we can directly retrieve the column values with the specified column names as follows:

 

Me.txtEname.Text = dtr("ename")
Me.txtSal.Text = dtr("sal")
Me.txtJob.Text = dtr("job")

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