Selezione delle colonne di input a livello di programmazione
Dopo aver connesso i componenti a livello di programmazione, selezionare le colonne dei componenti a monte che verranno trasformate o passate ai componenti a valle. Se non si selezionano colonne di input per il componente, quest'ultimo non riceve righe dall'attività Flusso di dati.
Selezione di colonne
Chiamare il metodo GetVirtualInput per recuperare l'elenco di colonne disponibili da un componente a monte, quindi chiamare il metodo SetUsageType dell'istanza della fase di progettazione del componente per selezionare colonne dalla raccolta di colonne di input virtuali. Quando si chiama questo metodo, il componente crea nella propria raccolta di colonne di input una nuova colonna con lo stesso ID di derivazione della colonna corrispondente presente nella raccolta di output del componente a monte.
Non selezionare le colonne chiamando direttamente il metodo SetUsageType dell'oggetto di input virtuale, perché altrimenti il componente non è più in grado di rifiutare colonne in base a tipi di dati o altre proprietà non appropriati.
Esempio
Nell'esempio di codice seguente è illustrato come utilizzare l'istanza della fase di progettazione di un componente per selezionare le colonne per un componente.
using System;
using Microsoft.SqlServer.Dts.Runtime;
using Microsoft.SqlServer.Dts.Pipeline;
using Microsoft.SqlServer.Dts.Pipeline.Wrapper;
namespace Microsoft.SqlServer.Dts.Samples
{
class Program
{
static void Main(string[] args)
{
// Create a package and add a Data Flow task.
Package package = new Package();
Executable e = package.Executables.Add("STOCK:PipelineTask");
TaskHost thMainPipe = e as TaskHost;
MainPipe dataFlowTask = thMainPipe.InnerObject as MainPipe;
// Add an OLE DB connection manager to the package.
ConnectionManager conMgr = package.Connections.Add("OLEDB");
conMgr.ConnectionString = "Provider=SQLOLEDB.1;" +
"Data Source=<servername>;Initial Catalog=AdventureWorks;" +
"Integrated Security=SSPI;";
conMgr.Name = "SSIS Connection Manager for OLE DB";
conMgr.Description = "OLE DB connection to the AdventureWorks database.";
// Create and configure an OLE DB source component.
IDTSComponentMetaData100 source =
dataFlowTask.ComponentMetaDataCollection.New();
source.ComponentClassID = "DTSAdapter.OleDbSource";
// Create the design-time instance of the source.
CManagedComponentWrapper srcDesignTime = source.Instantiate();
// The ProvideComponentProperties method creates a default output.
srcDesignTime.ProvideComponentProperties();
// Assign the connection manager.
source.RuntimeConnectionCollection[0].ConnectionManager =
DtsConvert.GetExtendedInterface(conMgr);
// Set the custom properties of the source.
srcDesignTime.SetComponentProperty("AccessMode", 2);
srcDesignTime.SetComponentProperty("SqlCommand",
"Select * from Production.Product");
// Connect to the data source,
// and then update the metadata for the source.
srcDesignTime.AcquireConnections(null);
srcDesignTime.ReinitializeMetaData();
srcDesignTime.ReleaseConnections();
// Create and configure an OLE DB destination.
IDTSComponentMetaData100 destination =
dataFlowTask.ComponentMetaDataCollection.New();
destination.ComponentClassID = "DTSAdapter.OleDbDestination";
// Create the design-time instance of the destination.
CManagedComponentWrapper destDesignTime = destination.Instantiate();
// The ProvideComponentProperties method creates a default input.
destDesignTime.ProvideComponentProperties();
// Create the path from source to destination.
IDTSPath100 path = dataFlowTask.PathCollection.New();
path.AttachPathAndPropagateNotifications(source.OutputCollection[0],
destination.InputCollection[0]);
// Get the destination's default input and virtual input.
IDTSInput100 input = destination.InputCollection[0];
IDTSVirtualInput100 vInput = input.GetVirtualInput();
// Iterate through the virtual input column collection.
foreach (IDTSVirtualInputColumn100 vColumn in vInput.VirtualInputColumnCollection)
{
// Call the SetUsageType method of the destination
// to add each available virtual input column as an input column.
destDesignTime.SetUsageType(
input.ID, vInput, vColumn.LineageID, DTSUsageType.UT_READONLY);
}
// Verify that the columns have been added to the input.
foreach (IDTSInputColumn100 inputColumn in destination.InputCollection[0].InputColumnCollection)
Console.WriteLine(inputColumn.Name);
Console.Read();
// Add other components to the data flow and connect them.
}
}
}
Imports Microsoft.SqlServer.Dts.Runtime
Imports Microsoft.SqlServer.Dts.Pipeline
Imports Microsoft.SqlServer.Dts.Pipeline.Wrapper
Module Module1
Sub Main()
' Create a package and add a Data Flow task.
Dim package As Microsoft.SqlServer.Dts.Runtime.Package = _
New Microsoft.SqlServer.Dts.Runtime.Package()
Dim e As Executable = package.Executables.Add("STOCK:PipelineTask")
Dim thMainPipe As Microsoft.SqlServer.Dts.Runtime.TaskHost = _
CType(e, Microsoft.SqlServer.Dts.Runtime.TaskHost)
Dim dataFlowTask As MainPipe = CType(thMainPipe.InnerObject, MainPipe)
' Add an OLE DB connection manager to the package.
Dim conMgr As ConnectionManager = package.Connections.Add("OLEDB")
conMgr.ConnectionString = "Provider=SQLOLEDB.1;" & _
"Data Source=<servername>;Initial Catalog=AdventureWorks;" & _
"Integrated Security=SSPI;"
conMgr.Name = "SSIS Connection Manager for OLE DB"
conMgr.Description = "OLE DB connection to the AdventureWorks database."
' Create and configure an OLE DB source component.
Dim source As IDTSComponentMetaData100 = _
dataFlowTask.ComponentMetaDataCollection.New
source.ComponentClassID = "DTSAdapter.OleDbSource"
' Create the design-time instance of the source.
Dim srcDesignTime As CManagedComponentWrapper = source.Instantiate
' The ProvideComponentProperties method creates a default output.
srcDesignTime.ProvideComponentProperties()
' Assign the connection manager.
source.RuntimeConnectionCollection(0).ConnectionManager = _
DtsConvert.GetExtendedInterface(conMgr)
' Set the custom properties of the source.
srcDesignTime.SetComponentProperty("AccessMode", 2)
srcDesignTime.SetComponentProperty("SqlCommand", _
"Select * from Production.Product")
' Connect to the data source,
' and then update the metadata for the source.
srcDesignTime.AcquireConnections(Nothing)
srcDesignTime.ReinitializeMetaData()
srcDesignTime.ReleaseConnections()
' Create and configure an OLE DB destination.
Dim destination As IDTSComponentMetaData100 = _
dataFlowTask.ComponentMetaDataCollection.New
destination.ComponentClassID = "DTSAdapter.OleDbDestination"
' Create the design-time instance of the destination.
Dim destDesignTime As CManagedComponentWrapper = destination.Instantiate
' The ProvideComponentProperties method creates a default input.
destDesignTime.ProvideComponentProperties()
' Create the path from source to destination.
Dim path As IDTSPath100 = dataFlowTask.PathCollection.New
path.AttachPathAndPropagateNotifications(source.OutputCollection(0), _
destination.InputCollection(0))
' Get the destination's default input and virtual input.
Dim input As IDTSInput100 = destination.InputCollection(0)
Dim vInput As IDTSVirtualInput100 = input.GetVirtualInput
' Iterate through the virtual input column collection.
For Each vColumn As IDTSVirtualInputColumn100 In vInput.VirtualInputColumnCollection
' Call the SetUsageType method of the destination
' to add each available virtual input column as an input column.
destDesignTime.SetUsageType(input.ID, vInput, vColumn.LineageID, DTSUsageType.UT_READONLY)
Next
' Verify that the columns have been added to the input.
For Each inputColumn As IDTSInputColumn100 In destination.InputCollection(0).InputColumnCollection
Console.WriteLine(inputColumn.Name)
Next
Console.Read()
' Add other components to the data flow and connect them.
End Sub
End Module
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