ExecutePageReader Method

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

Syntax

Visual Basic
C#


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


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

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(BigQueryConnection bigQueryConnection, int StartRow, int PageLength) { BigQueryCommand bigQueryCommand = new BigQueryCommand("SELECT id, first_name, last_name FROM your_project.your_dataset.employees", bigQueryConnection); bigQueryConnection.Open(); BigQueryDataReader bigQueryReader = bigQueryCommand.ExecutePageReader(System.Data.CommandBehavior.Default,StartRow,PageLength); try { while (bigQueryReader.Read()) { Console.WriteLine(bigQueryReader.GetInt64(0) + ", " + bigQueryReader.GetString(1) + ", " + bigQueryReader.GetString(2)); } } finally { bigQueryReader.Close(); bigQueryConnection.Close(); } }

public void ExecutePaged(BigQueryConnection bigQueryConnection, int StartRow, int PageLength)
{
  BigQueryCommand bigQueryCommand = new BigQueryCommand("SELECT id, first_name, last_name FROM your_project.your_dataset.employees", bigQueryConnection);
  bigQueryConnection.Open();
  BigQueryDataReader bigQueryReader = bigQueryCommand.ExecutePageReader(System.Data.CommandBehavior.Default,StartRow,PageLength);
  try
  {
    while (bigQueryReader.Read())
    {
        Console.WriteLine(bigQueryReader.GetInt64(0) + ", " + bigQueryReader.GetString(1) + ", " + bigQueryReader.GetString(2));
    }
  }
  finally
  {
    bigQueryReader.Close();
    bigQueryConnection.Close();
  }
}

Visual Basic


Public Sub ExecutePaged(ByVal bigQueryConnection As BigQueryConnection, ByVal StartRow As Integer, ByVal PageLength As Integer) Dim bigQueryCommand As New BigQueryCommand("SELECT id, first_name, last_name FROM your_project.your_dataset.employees", bigQueryConnection) bigQueryConnection.Open() Dim bigQueryReader As BigQueryDataReader = bigQueryCommand.ExecutePageReader(System.Data.CommandBehavior.Default, StartRow, PageLength) Try While bigQueryReader.Read() Console.WriteLine(bigQueryReader.GetInt64(0) + ", " _ + bigQueryReader.GetString(1) + ", " _ + bigQueryReader.GetString(2)) End While Finally bigQueryReader.Close() bigQueryConnection.Close() End Try End Sub

Public Sub ExecutePaged(ByVal bigQueryConnection As BigQueryConnection, ByVal StartRow As Integer, ByVal PageLength As Integer)
  Dim bigQueryCommand As New BigQueryCommand("SELECT id, first_name, last_name FROM your_project.your_dataset.employees", bigQueryConnection)
  bigQueryConnection.Open()
  Dim bigQueryReader As BigQueryDataReader = bigQueryCommand.ExecutePageReader(System.Data.CommandBehavior.Default, StartRow, PageLength)
  Try
    While bigQueryReader.Read()
      Console.WriteLine(bigQueryReader.GetInt64(0) + ", " _
      + bigQueryReader.GetString(1) + ", " _
      + bigQueryReader.GetString(2))
    End While
  Finally
    bigQueryReader.Close()
    bigQueryConnection.Close()
  End Try
End Sub

Reference

DbCommandBase Class
DbCommandBase Members

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