IDTSBufferManager90.FindColumnByLineageID Method

Artykuł
12/03/2008

Gets the location, by index, of a column in a specified IDTSBuffer90 object.

Namespace: Microsoft.SqlServer.Dts.Pipeline.Wrapper
Assembly: Microsoft.SqlServer.DTSPipelineWrap (in microsoft.sqlserver.dtspipelinewrap.dll)

Syntax

'Declaration
<DispIdAttribute(121)> _
Function FindColumnByLineageID ( _
    <InAttribute> hBufferType As Integer, _
    <InAttribute> nLineageID As Integer _
) As Integer

[DispIdAttribute(121)] 
int FindColumnByLineageID (
    [InAttribute] int hBufferType,
    [InAttribute] int nLineageID
)

[DispIdAttribute(121)] 
int FindColumnByLineageID (
    [InAttribute] int hBufferType, 
    [InAttribute] int nLineageID
)

/** @attribute DispIdAttribute(121) */ 
int FindColumnByLineageID (
    /** @attribute InAttribute() */ int hBufferType, 
    /** @attribute InAttribute() */ int nLineageID
)

DispIdAttribute(121) 
function FindColumnByLineageID (
    hBufferType : int, 
    nLineageID : int
) : int

Parameters

hBufferType
The ID of the IDTSBuffer90 object that contains the column.

nLineageID
The lineage ID of the column to locate in the IDTSBuffer90.

Return Value

An integer that indicates the location, by index, of the column in the IDTSBuffer90.

Remarks

This method locates the column of an IDTSInput90 or IDTSOutput90 in the specified IDTSBuffer90. This method is necessary because an instance of a buffer contains all of the IDTSOutputColumn90 objects defined in the IDTSOutputColumnCollection90 collections of the components in a graph. Components cannot rely on using the index location of its output column, or input column, as the index of that column in a buffer row. Because of this, components must use FindColumnByLineageID to locate the columns in the buffer.

Example

The following code example shows how a transformation component that does not have output columns uses the FindColumnByLineageID to locate its input columns in the buffer.

int[] bufferColumnIndex;
public override void PreExecute()
{
    IDTSInput90 input = ComponentMetaData.InputCollection[0];
    bufferColumnIndex = new int[BufferManager.GetColumnCount(input.Buffer)];

    for( int col=0; col < input.InputColumnCollection.Count; col++)
    {
        IDTSInputColumn90 iCol = input.InputColumnCollection[col];
        bufferColumnIndex[col] = BufferManager.FindColumnByLineageID(input.Buffer, iCol.LineageID);
    }
}

Private bufferColumnIndex As Integer() 

Public Overloads Overrides Sub PreExecute() 
 Dim input As IDTSInput90 = ComponentMetaData.InputCollection(0) 
 bufferColumnIndex = New Integer(BufferManager.GetColumnCount(input.Buffer) - 1) {} 
 Dim col As Integer = 0 
 While col < input.InputColumnCollection.Count 
   Dim iCol As IDTSInputColumn90 = input.InputColumnCollection(col) 
   bufferColumnIndex(col) = BufferManager.FindColumnByLineageID(input.Buffer, iCol.LineageID) 
   col -= 1 
 End While 
End Sub

Thread Safety

Any public static (Shared in Microsoft Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Platforms

Development Platforms

For a list of the supported platforms, see Hardware and Software Requirements for Installing SQL Server 2005.

Target Platforms