SqlBulkCopy.BatchSize Egenskap

public:
 property int BatchSize { int get(); void set(int value); };

public int BatchSize { get; set; }

member this.BatchSize : int with get, set

Public Property BatchSize As Integer

Egenskapsvärde

Heltalsvärdet för BatchSize egenskapen eller noll om inget värde har angetts.

Exempel

Följande konsolprogram visar hur du massinläser data i batchar med 50 rader. Ett exempel som illustrerar hur BatchSize fungerar med en transaktion finns i Transaktions- och masskopieringsåtgärder.

I det här exemplet läss källdata först från en SQL Server-tabell till en SqlDataReader-instans. Källdata behöver inte finnas på SQL Server. Du kan använda alla datakällor som kan läsas till en IDataReader eller läsas in på en DataTable.

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.BulkCopyDemoMatchingColumns;",
                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();

            // Create the SqlBulkCopy object using a connection string.
            // In the real world you would not use SqlBulkCopy to move
            // data from one table to the other in the same database.
            using (SqlBulkCopy bulkCopy = new SqlBulkCopy(connectionString))
            {
                bulkCopy.DestinationTableName =
                    "dbo.BulkCopyDemoMatchingColumns";

                // Set the BatchSize.
                bulkCopy.BatchSize = 50;

                try
                {
                    // Write from the source to the destination.
                    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.BulkCopyDemoMatchingColumns;", _
                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

            ' Create the SqlBulkCopy object using a connection string. 
            ' In the real world you would not use SqlBulkCopy to move
            ' data from one table to the other in the same database.
            Using bulkCopy As SqlBulkCopy = _
              New SqlBulkCopy(connectionString)
                bulkCopy.DestinationTableName = "dbo.BulkCopyDemoMatchingColumns"

                ' Set the BatchSize.
                bulkCopy.BatchSize = 50

                Try
                    ' Write from the source to the destination.
                    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

Kommentarer

En batch är klar när BatchSize rader har bearbetats eller det inte finns några fler rader att skicka till måldatakällan.

Noll (standardvärdet) anger att varje WriteToServer åtgärd är en enda batch.

Om instansen SqlBulkCopy har deklarerats utan det UseInternalTransaction gällande alternativet skickas rader till serverraderna BatchSize i taget, men ingen transaktionsrelaterad åtgärd vidtas. Om UseInternalTransaction gäller infogas varje batch med rader som en separat transaktion.

Egenskapen BatchSize kan ställas in när som helst. Om en masskopia redan pågår, storleksanpassas den aktuella batchen enligt den tidigare batchstorleken. Efterföljande batchar använder den nya storleken. BatchSize Om är initialt noll och ändras medan en WriteToServer åtgärd redan pågår läser åtgärden in data som en enda batch. Alla efterföljande WriteToServer åtgärder på samma SqlBulkCopy instans använder den nya BatchSize.

Se även

• Masskopieringsåtgärder i SQL Server
• översikt över ADO.NET