ExecutePageReader Method (DbCommandBase)

In This Topic

Syntax
Remarks
Example
See Also

Returns a specific subset of rows when paging through the results of a query.

Syntax

Visual Basic
C#

public DbDataReader ExecutePageReader( 
   CommandBehavior behavior,
   int startRecord,
   int maxRecords
)

'Declaration
 
Public Function ExecutePageReader( _
   ByVal behavior As CommandBehavior, _
   ByVal startRecord As Integer, _
   ByVal maxRecords As Integer _
) As DbDataReader

Parameters

behavior: One of the System.Data.CommandBehavior values.
startRecord: Zero-based ordinal of row that result set starts with.
maxRecords: Quantity of rows in result set.

Return Value

A DbDataReaderBase object.

Remarks

Use method ExecutePageReader when you want to retrieve not the whole dataset but some part of it that begins with given row number and has certain quantity of rows. This is especially useful when working with large amounts of data.

If you want to retrieve all data in a dataset, use System.Data.Common.DbCommandBase.ExecuteReader() instead.

Example

The example below shows how to retrieve a part of a table. If this function is called with parameters startRecord=2 and maxRecords=3, it returns 3 rows: second, third, and fourth.

csharp

public void ExecutePaged(DB2Connection db2Connection, int StartRow, int PageLength)
{
  DB2Command db2Command = new DB2Command("SELECT DeptNo, DName, Loc FROM Dept", db2Connection);
  db2Connection.Open();
  DB2DataReader db2Reader = db2Command.ExecutePageReader(System.Data.CommandBehavior.Default,StartRow,PageLength);
  try
  {
    while (db2Reader.Read())
    {
        Console.WriteLine(db2Reader.GetInt32(0).ToString() + ", " + db2Reader.GetString(1) + ", " + db2Reader.GetString(2));
    }
  }
  finally
  {
    db2Reader.Close();
    db2Connection.Close();
  }
}

Visual Basic

Public Sub ExecutePaged(ByVal db2Connection As DB2Connection, ByVal StartRow As Integer, ByVal PageLength As Integer)
  Dim db2Command As New DB2Command("SELECT DeptNo, DName, Loc FROM Dept", db2Connection)
  db2Connection.Open()
  Dim db2Reader As DB2DataReader = db2Command.ExecutePageReader(System.Data.CommandBehavior.Default, StartRow, PageLength)
  Try
    While db2Reader.Read()
      Console.WriteLine(db2Reader.GetInt32(0).ToString() + ", " _
      + db2Reader.GetString(1) + ", " _
      + db2Reader.GetString(2))
    End While
  Finally
    db2Reader.Close()
    db2Connection.Close()
  End Try
End Sub

Reference

DbCommandBase Class
DbCommandBase Members

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