PipelineComponent.PreExecute Method

Artigo
12/03/2008

Called after PrepareForExecute, and before PrimeOutput and ProcessInput.

Namespace: Microsoft.SqlServer.Dts.Pipeline
Assembly: Microsoft.SqlServer.PipelineHost (in microsoft.sqlserver.pipelinehost.dll)

Syntax

'Declaration
Public Overridable Sub PreExecute

public virtual void PreExecute ()

public:
virtual void PreExecute ()

public void PreExecute ()

public function PreExecute ()

Remarks

Component developers should factor as much functionality into PreExecute as possible because it is called one time per component instead of one time per buffer for ProcessInput. Components should locate the indexes of its input and output columns in the PipelineBuffer by calling the FindColumnByLineageID method of the BufferManager.

Example

The following example shows how to locate the column indexes of the columns in the InputColumnCollection. They are stored in a local variable and then used in ProcessInput to access the columns in the PipelineBuffer.

int[] bufferColumnIndex;
public override void PreExecute()
{
    IDTSInput90 input = ComponentMetaData.InputCollection[0];
    bufferColumnIndex = new int[input.InputColumnCollection.Count];
    for ( int x=0; x < input.InputColumnCollection.Count; x++)
    {
        bufferColumnIndex[x] = BufferManager.FindColumnByLineageID( input.Buffer, input.InputColumnCollection[x].LineageID);
    }
}
public override void ProcessInput( int inputID, PipelineBuffer buffer )
{
    if( !buffer.EndOfRowset)
    {
        while( buffer.NextRow() )
        {
            for( int x=0; x < bufferColumnIndex.Length(); x++ )
            {
                if( !buffer.IsNull(bufferColumnIndex[x]))
                {
                    // TODO: Access the column data.
                }
            }
        }
    }
}

Private bufferColumnIndex As Integer() 

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

Public Overrides Sub ProcessInput(ByVal inputID As Integer, ByVal buffer As PipelineBuffer) 
 If Not buffer.EndOfRowset Then 
   While buffer.NextRow 
     Dim x As Integer = 0 
     While x < bufferColumnIndex.Length 
       If Not buffer.IsNull(bufferColumnIndex(x)) Then 
       End If 
       x -= 1
     End While 
   End While 
 End If 
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

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

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