SqlBulkCopyColumnMapping.DestinationColumn Vlastnost

Definice

Obor názvů:

System.Data.SqlClient

Sestavení:

System.Data.dll

Název sloupce mapovaného v cílové tabulce databáze

public:
 property System::String ^ DestinationColumn { System::String ^ get(); void set(System::String ^ value); };

public string DestinationColumn { get; set; }

member this.DestinationColumn : string with get, set

Public Property DestinationColumn As String

Hodnota vlastnosti

String

Řetězcová hodnota DestinationColumn vlastnosti.

Příklady

Následující příklad hromadně zkopíruje data ze zdrojové tabulky v ukázkové databázi AdventureWorks do cílové tabulky ve stejné databázi. I když počet sloupců v cíli odpovídá počtu sloupců ve zdroji, názvy sloupců a pořadí řad se neshodují. SqlBulkCopyColumnMapping objekty se používají k vytvoření mapy sloupců pro hromadné kopírování.

Důležité

Tato ukázka se nespustí, pokud jste nevytvořili pracovní tabulky, jak je popsáno v příkladu hromadného kopírování. Tento kód je k dispozici k předvedení syntaxe pouze pro použití SqlBulkCopy . Pokud jsou zdrojová a cílová tabulka ve stejné SQL Server instanci, je jednodušší a rychlejší zkopírovat data pomocí příkazu Jazyka Transact-SQLINSERT … SELECT.

using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = GetConnectionString();
        // Open a sourceConnection to the AdventureWorks database.
        using (SqlConnection sourceConnection =
                   new SqlConnection(connectionString))
        {
            sourceConnection.Open();

            // Perform an initial count on the destination table.
            SqlCommand commandRowCount = new SqlCommand(
                "SELECT COUNT(*) FROM " +
                "dbo.BulkCopyDemoDifferentColumns;",
                sourceConnection);
            long countStart = System.Convert.ToInt32(
                commandRowCount.ExecuteScalar());
            Console.WriteLine("Starting row count = {0}", countStart);

            // Get data from the source table as a SqlDataReader.
            SqlCommand commandSourceData = new SqlCommand(
                "SELECT ProductID, Name, " +
                "ProductNumber " +
                "FROM Production.Product;", sourceConnection);
            SqlDataReader reader =
                commandSourceData.ExecuteReader();

            // Set up the bulk copy object.
            using (SqlBulkCopy bulkCopy =
                       new SqlBulkCopy(connectionString))
            {
                bulkCopy.DestinationTableName =
                    "dbo.BulkCopyDemoDifferentColumns";

                // Set up the column mappings source and destination.
                SqlBulkCopyColumnMapping mapID = new SqlBulkCopyColumnMapping();
                mapID.SourceColumn = "ProductID";
                mapID.DestinationColumn = "ProdID";
                bulkCopy.ColumnMappings.Add(mapID);

                SqlBulkCopyColumnMapping mapName = new SqlBulkCopyColumnMapping();
                mapName.SourceColumn = "Name";
                mapName.DestinationColumn = "ProdName";
                bulkCopy.ColumnMappings.Add(mapName);

                SqlBulkCopyColumnMapping mapNumber = new SqlBulkCopyColumnMapping();
                mapNumber.SourceColumn = "ProductNumber";
                mapNumber.DestinationColumn = "ProdNum";
                bulkCopy.ColumnMappings.Add(mapNumber);

                // Write from the source to the destination.
                try
                {
                    bulkCopy.WriteToServer(reader);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
                finally
                {
                    // Close the SqlDataReader. The SqlBulkCopy
                    // object is automatically closed at the end
                    // of the using block.
                    reader.Close();
                }
            }

            // Perform a final count on the destination
            // table to see how many rows were added.
            long countEnd = System.Convert.ToInt32(
                commandRowCount.ExecuteScalar());
            Console.WriteLine("Ending row count = {0}", countEnd);
            Console.WriteLine("{0} rows were added.", countEnd - countStart);
            Console.WriteLine("Press Enter to finish.");
            Console.ReadLine();
        }
    }

    private static string GetConnectionString()
        // To avoid storing the sourceConnection string in your code,
        // you can retrieve it from a configuration file.
    {
        return "Data Source=(local); " +
            " Integrated Security=true;" +
            "Initial Catalog=AdventureWorks;";
    }
}

Imports System.Data.SqlClient

Module Module1
    Sub Main()
        Dim connectionString As String = GetConnectionString()

        ' Open a connection to the AdventureWorks database.
        Using sourceConnection As SqlConnection = _
           New SqlConnection(connectionString)
            sourceConnection.Open()

            ' Perform an initial count on the destination table.
            Dim commandRowCount As New SqlCommand( _
            "SELECT COUNT(*) FROM dbo.BulkCopyDemoDifferentColumns;", _
                sourceConnection)
            Dim countStart As Long = _
               System.Convert.ToInt32(commandRowCount.ExecuteScalar())
            Console.WriteLine("Starting row count = {0}", countStart)

            ' Get data from the source table as a SqlDataReader.
            Dim commandSourceData As SqlCommand = New SqlCommand( _
               "SELECT ProductID, Name, ProductNumber " & _
               "FROM Production.Product;", sourceConnection)
            Dim reader As SqlDataReader = commandSourceData.ExecuteReader

            ' Set up the bulk copy object.
            Using bulkCopy As SqlBulkCopy = New SqlBulkCopy(connectionString)
                bulkCopy.DestinationTableName = _
                "dbo.BulkCopyDemoDifferentColumns"

                ' Set up the column mappings source and destination.
                Dim mapID As New SqlBulkCopyColumnMapping()
                mapID.SourceColumn = "ProductID"
                mapID.DestinationColumn = "ProdID"
                bulkCopy.ColumnMappings.Add(mapID)

                Dim mapName As New SqlBulkCopyColumnMapping()
                mapName.SourceColumn = "Name"
                mapName.DestinationColumn = "ProdName"
                bulkCopy.ColumnMappings.Add(mapName)

                Dim mapNumber As New SqlBulkCopyColumnMapping()
                mapNumber.SourceColumn = "ProductNumber"
                mapNumber.DestinationColumn = "ProdNum"
                bulkCopy.ColumnMappings.Add(mapNumber)

                ' Write from the source to the destination.
                Try
                    bulkCopy.WriteToServer(reader)

                Catch ex As Exception
                    Console.WriteLine(ex.Message)

                Finally
                    ' Close the SqlDataReader. The SqlBulkCopy
                    ' object is automatically closed at the end
                    ' of the Using block.
                    reader.Close()
                End Try
            End Using

            ' Perform a final count on the destination table
            ' to see how many rows were added.
            Dim countEnd As Long = _
                System.Convert.ToInt32(commandRowCount.ExecuteScalar())
            Console.WriteLine("Ending row count = {0}", countEnd)
            Console.WriteLine("{0} rows were added.", countEnd - countStart)

            Console.WriteLine("Press Enter to finish.")
            Console.ReadLine()
        End Using
    End Sub

    Private Function GetConnectionString() As String
        ' To avoid storing the sourceConnection string in your code, 
        ' you can retrieve it from a configuration file. 
        Return "Data Source=(local);" & _
            "Integrated Security=true;" & _
            "Initial Catalog=AdventureWorks;"
    End Function
End Module

Poznámky

Vlastnosti DestinationColumn a DestinationOrdinal se vzájemně vylučují. Poslední sada hodnot má přednost.

Viz také

• Operace hromadného kopírování na SQL Serveru
• Přehled ADO.NET