DbRangeOptions Enumeration

Článek
10/22/2009

Specifies the options used by the SetRange method when specifying the index range over which to seek.

Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (in system.data.sqlserverce.dll)

Syntax

'Declaration
<FlagsAttribute> _
Public Enumeration DbRangeOptions

[FlagsAttribute] 
public enum DbRangeOptions

[FlagsAttribute] 
public enum class DbRangeOptions

/** @attribute FlagsAttribute() */ 
public enum DbRangeOptions

FlagsAttribute 
public enum DbRangeOptions

Members

Member name	Description
Default	Equivalent to setting both the InclusiveStart and InclusiveEnd flags.
ExcludeNulls	Excludes null values from the range.
ExclusiveEnd	Excludes the endData value from the range.
ExclusiveStart	Excludes the startData value from the range.
InclusiveEnd	Includes the endData value in the range.
InclusiveStart	Includes the startData value in the range.
Match	Specifies a range in which index values match the value of startData. When using the Match option, endData must be set to null.
Prefix	Specifies a range in which index values begin with the value of startData. When using the Prefix option, endData must be set to null.

Remarks

If you specify the Match or Prefix option, the endData value must be null.

You cannot combine the Match and ExcludeNulls options.

Example

In this example, the range options for the Seek operation on the index are specified as InclusiveStart or InclusiveEnd when calling the SetRange method.

Try
    Dim conn As New SqlCeConnection("Data Source = MyDatabase.sdf")
    conn.Open()

    Dim cmd As SqlCeCommand = conn.CreateCommand()
    cmd.CommandType = CommandType.TableDirect
    cmd.IndexName = "Orders_PK"
    cmd.CommandText = "Orders"

    ' We are interested in orders that match Order ID = 10020
    '
    cmd.SetRange(DbRangeOptions.Match, New Object() {10020}, Nothing)

    Dim reader As SqlCeDataReader = cmd.ExecuteReader(CommandBehavior.Default)

    While reader.Read()
        MessageBox.Show(String.Format("{0} ; {1}", reader("Order ID"), reader("Order Date")))
    End While

    ' Now we are interested in orders with Order ID between (10020, 10050)
    '
    cmd.SetRange(DbRangeOptions.InclusiveStart Or DbRangeOptions.InclusiveEnd, New Object() {10020}, New Object() {10050})

    reader = cmd.ExecuteReader(CommandBehavior.Default)

    ' Now seek to Order ID = 10045
    '
    Dim onRow As Boolean =  reader.Seek(DbSeekOptions.FirstEqual, New Object() {10045})

    ' Now ,the reader will return rows with Order ID >= 10045 <= 10050
    ' because the range was set to (10020, 10050)
    '
    If onRow Then
        While reader.Read()
            MessageBox.Show(String.Format("{0} ; {1}", reader("Order ID"), reader("Order Date")))
        End While
    End If
Catch e As Exception
    MessageBox.Show(e.Message)
End Try

try
{
    SqlCeConnection conn = new SqlCeConnection("Data Source = MyDatabase.sdf");
    conn.Open();

    SqlCeCommand cmd = conn.CreateCommand();
    cmd.CommandType = CommandType.TableDirect;
    cmd.IndexName = "Orders_PK";
    cmd.CommandText = "Orders";

    // We are interested in orders that match Order ID = 10020
    //
    cmd.SetRange(DbRangeOptions.Match, new object[] { 10020 }, null);

    SqlCeDataReader reader = cmd.ExecuteReader(CommandBehavior.Default);

    for (int i = 1; reader.Read(); i++)
    {
        MessageBox.Show(String.Format("{0} ; {1}", reader["Order ID"], reader["Order Date"]));
    }

    // Now we are interested in orders with Order ID between (10020, 10050)
    //
    cmd.SetRange(DbRangeOptions.InclusiveStart | DbRangeOptions.InclusiveEnd,
        new object[] { 10020 }, new object[] { 10050 });

    reader = cmd.ExecuteReader(CommandBehavior.Default);

    // Now seek to Order ID = 10045
    //
    bool onRow = reader.Seek(DbSeekOptions.FirstEqual, new object[] { 10045 });

    // Now ,the reader will return rows with Order ID >= 10045 <= 10050
    // because the range was set to (10020, 10050)
    //
    if (onRow)
    {
        for (int i = 1; reader.Read(); i++)
        {
            MessageBox.Show(String.Format("{0} ; {1}", reader["Order ID"], reader["Order Date"]));
        }
    }
}
catch (Exception e)
{
    MessageBox.Show(e.Message);
}

Platforms

Development Platforms

Windows Vista, Windows Mobile 5.0, Windows XP Professional with Service Pack 2 (SP2), Windows Server 2003, Windows Mobile 2003 for Pocket PC, Windows CE 5.0
Version Information
.NET Framework and NET Compact Framework
Supported in 3.5
.NET Framework
Supported in 3.0
.NET Compact Framework and .Net Framework
Supported in 2.0

Sdílet prostřednictvím