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Несколько операций массового копирования

Можно выполнять несколько операций массового копирования с одним экземпляром SqlBulkCopy класса. Если параметры операции изменяются между копиями (например, имя целевой таблицы), обновите их перед следующим вызовом WriteToServer. Если вы не измените их, значения свойств остаются одинаковыми между операциями с одним и тем же экземпляром.

Примечание.

Выполнение нескольких операций массового копирования с помощью одного экземпляра SqlBulkCopy обычно более эффективно, чем использование отдельного экземпляра для каждой операции.

При выполнении нескольких операций массового копирования с помощью одного и того же объекта SqlBulkCopy нет ограничений на то, равны ли исходные или целевые сведения в каждой операции. Однако необходимо убедиться, что сведения о сопоставлении столбцов устанавливаются правильно при каждой записи на сервер.

Это важно

Перед запуском этого примера создайте рабочие таблицы, описанные в разделе Настройка примера массового копирования. В примере показан SqlBulkCopy синтаксис. Если исходные и целевые таблицы находятся в одном экземпляре SQL Server, используйте инструкцию Transact-SQL (T-SQL) INSERT ... SELECT для ускорения копирования.

Чтобы сохранить связь между заказами и их подробностями, в этом примере указывается SqlBulkCopyOptions.KeepIdentity. В таблице конечного заголовка есть столбец идентификатора, поэтому копия должна сохранять исходные SalesOrderID значения, на которые ссылались строки сведений. Одни лишь сопоставления столбцов не сохраняют значения идентификаторов.

static void Main()
{
    var connectionString = GetConnectionString();
    // Open a connection to the AdventureWorks database.
    using (SqlConnection connection =
               new(connectionString))
    {
        connection.Open();

        // Empty the destination tables.
        SqlCommand deleteHeader = new(
            "DELETE FROM dbo.BulkCopyDemoOrderHeader;",
            connection);
        deleteHeader.ExecuteNonQuery();
        SqlCommand deleteDetail = new(
            "DELETE FROM dbo.BulkCopyDemoOrderDetail;",
            connection);
        deleteDetail.ExecuteNonQuery();

        // Perform an initial count on the destination
        //  table with matching columns.
        SqlCommand countRowHeader = new(
            "SELECT COUNT(*) FROM dbo.BulkCopyDemoOrderHeader;",
            connection);
        long countStartHeader = Convert.ToInt32(
            countRowHeader.ExecuteScalar());
        Console.WriteLine($"Starting row count for Header table = {countStartHeader}");

        // Perform an initial count on the destination
        // table with different column positions.
        SqlCommand countRowDetail = new(
            "SELECT COUNT(*) FROM dbo.BulkCopyDemoOrderDetail;",
            connection);
        long countStartDetail = Convert.ToInt32(
            countRowDetail.ExecuteScalar());
        Console.WriteLine($"Starting row count for Detail table = {countStartDetail}");

        // Get data from the source table as a SqlDataReader.
        // The Sales.SalesOrderHeader and Sales.SalesOrderDetail
        // tables are quite large and could easily cause a timeout
        // if all data from the tables is added to the destination.
        // To keep the example simple and quick, a parameter is
        // used to select only orders for a particular account
        // as the source for the bulk insert.
        SqlCommand headerData = new(
            "SELECT [SalesOrderID], [OrderDate], " +
            "[AccountNumber] FROM [Sales].[SalesOrderHeader] " +
            "WHERE [AccountNumber] = @accountNumber;",
            connection);
        SqlParameter parameterAccount = new()
        {
            ParameterName = "@accountNumber",
            SqlDbType = SqlDbType.NVarChar,
            Direction = ParameterDirection.Input,
            Value = "10-4020-000034"
        };
        headerData.Parameters.Add(parameterAccount);
        SqlDataReader readerHeader = headerData.ExecuteReader();

        // Get the Detail data in a separate connection.
        using (SqlConnection connection2 = new(connectionString))
        {
            connection2.Open();
            SqlCommand sourceDetailData = new(
                "SELECT [Sales].[SalesOrderDetail].[SalesOrderID], [SalesOrderDetailID], " +
                "[OrderQty], [ProductID], [UnitPrice] FROM [Sales].[SalesOrderDetail] " +
                "INNER JOIN [Sales].[SalesOrderHeader] ON [Sales].[SalesOrderDetail]." +
                "[SalesOrderID] = [Sales].[SalesOrderHeader].[SalesOrderID] " +
                "WHERE [AccountNumber] = @accountNumber;", connection2);

            SqlParameter accountDetail = new()
            {
                ParameterName = "@accountNumber",
                SqlDbType = SqlDbType.NVarChar,
                Direction = ParameterDirection.Input,
                Value = "10-4020-000034"
            };
            sourceDetailData.Parameters.Add(accountDetail);
            SqlDataReader readerDetail = sourceDetailData.ExecuteReader();

            // Create the SqlBulkCopy object.
            using (SqlBulkCopy bulkCopy =
                       new(connectionString, SqlBulkCopyOptions.KeepIdentity))
            {
                bulkCopy.DestinationTableName =
                    "dbo.BulkCopyDemoOrderHeader";

                // Guarantee that columns are mapped correctly by
                // defining the column mappings for the order.
                bulkCopy.ColumnMappings.Add("SalesOrderID", "SalesOrderID");
                bulkCopy.ColumnMappings.Add("OrderDate", "OrderDate");
                bulkCopy.ColumnMappings.Add("AccountNumber", "AccountNumber");

                // Write readerHeader to the destination.
                try
                {
                    bulkCopy.WriteToServer(readerHeader);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
                finally
                {
                    readerHeader.Close();
                }

                // Set up the order details destination.
                bulkCopy.DestinationTableName = "dbo.BulkCopyDemoOrderDetail";

                // Clear the ColumnMappingCollection.
                bulkCopy.ColumnMappings.Clear();

                // Add order detail column mappings.
                bulkCopy.ColumnMappings.Add("SalesOrderID", "SalesOrderID");
                bulkCopy.ColumnMappings.Add("SalesOrderDetailID", "SalesOrderDetailID");
                bulkCopy.ColumnMappings.Add("OrderQty", "OrderQty");
                bulkCopy.ColumnMappings.Add("ProductID", "ProductID");
                bulkCopy.ColumnMappings.Add("UnitPrice", "UnitPrice");

                // Write readerDetail to the destination.
                try
                {
                    bulkCopy.WriteToServer(readerDetail);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
                finally
                {
                    readerDetail.Close();
                }
            }

            // Perform a final count on the destination
            // tables to see how many rows were added.
            long countEndHeader = Convert.ToInt32(
                countRowHeader.ExecuteScalar());
            Console.WriteLine($"{countEndHeader - countStartHeader} rows were added to the Header table.");
            long countEndDetail = Convert.ToInt32(
                countRowDetail.ExecuteScalar());
            Console.WriteLine($"{countEndDetail - countStartDetail} rows were added to the Detail table.");
            Console.WriteLine("Press Enter to finish.");
            Console.ReadLine();
        }
    }
}

Imports Microsoft.Data.SqlClient

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

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

            ' Empty the destination tables.
            Dim deleteHeader As New SqlCommand( _
              "DELETE FROM dbo.BulkCopyDemoOrderHeader;", connection)
            deleteHeader.ExecuteNonQuery()
            deleteHeader.Dispose()
            Dim deleteDetail As New SqlCommand( _
              "DELETE FROM dbo.BulkCopyDemoOrderDetail;", connection)
            deleteDetail.ExecuteNonQuery()

            ' Perform an initial count on the destination table
            ' with matching columns.
            Dim countRowHeader As New SqlCommand( _
               "SELECT COUNT(*) FROM dbo.BulkCopyDemoOrderHeader;", _
                connection)
            Dim countStartHeader As Long = System.Convert.ToInt32( _
             countRowHeader.ExecuteScalar())
            Console.WriteLine("Starting row count for Header table = {0}", _
             countStartHeader)

            ' Perform an initial count on the destination table
            ' with different column positions.
            Dim countRowDetail As New SqlCommand( _
                "SELECT COUNT(*) FROM dbo.BulkCopyDemoOrderDetail;", _
                connection)
            Dim countStartDetail As Long = System.Convert.ToInt32( _
                countRowDetail.ExecuteScalar())
            Console.WriteLine("Starting row count for Detail table = " & _
               countStartDetail)

            ' Get data from the source table as a SqlDataReader.
            ' The Sales.SalesOrderHeader and Sales.SalesOrderDetail
            ' tables are quite large and could easily cause a timeout
            ' if all data from the tables is added to the destination.
            ' To keep the example simple and quick, a parameter is
            ' used to select only orders for a particular account as
            ' the source for the bulk insert.
            Dim headerData As SqlCommand = New SqlCommand( _
             "SELECT [SalesOrderID], [OrderDate], " & _
             "[AccountNumber] FROM [Sales].[SalesOrderHeader] " & _
             "WHERE [AccountNumber] = @accountNumber;", _
             connection)

            Dim parameterAccount As SqlParameter = New SqlParameter()
            parameterAccount.ParameterName = "@accountNumber"
            parameterAccount.SqlDbType = SqlDbType.NVarChar
            parameterAccount.Direction = ParameterDirection.Input
            parameterAccount.Value = "10-4020-000034"
            headerData.Parameters.Add(parameterAccount)

            Dim readerHeader As SqlDataReader = _
             headerData.ExecuteReader()

            ' Get the Detail data in a separate connection.
            Using connection2 As SqlConnection = New SqlConnection(connectionString)
                connection2.Open()

                Dim sourceDetailData As SqlCommand = New SqlCommand( _
                 "SELECT [Sales].[SalesOrderDetail].[SalesOrderID], " & _
                 "[SalesOrderDetailID], [OrderQty], [ProductID], [UnitPrice] " & _
                 "FROM [Sales].[SalesOrderDetail] INNER JOIN " & _
                 "[Sales].[SalesOrderHeader] " & _
                 "ON [Sales].[SalesOrderDetail].[SalesOrderID] = " & _
                 "[Sales].[SalesOrderHeader].[SalesOrderID] " & _
                 "WHERE [AccountNumber] = @accountNumber;", connection2)

                Dim accountDetail As SqlParameter = New SqlParameter()
                accountDetail.ParameterName = "@accountNumber"
                accountDetail.SqlDbType = SqlDbType.NVarChar
                accountDetail.Direction = ParameterDirection.Input
                accountDetail.Value = "10-4020-000034"
                sourceDetailData.Parameters.Add( _
                 accountDetail)

                Dim readerDetail As SqlDataReader = _
                 sourceDetailData.ExecuteReader()

                ' Create the SqlBulkCopy object.
                Using bulkCopy As SqlBulkCopy = _
                  New SqlBulkCopy(connectionString, SqlBulkCopyOptions.KeepIdentity)
                    bulkCopy.DestinationTableName = "dbo.BulkCopyDemoOrderHeader"

                    ' Guarantee that columns are mapped correctly by
                    ' defining the column mappings for the order.
                    bulkCopy.ColumnMappings.Add("SalesOrderID", "SalesOrderID")
                    bulkCopy.ColumnMappings.Add("OrderDate", "OrderDate")
                    bulkCopy.ColumnMappings.Add("AccountNumber", "AccountNumber")

                    ' Write readerHeader to the destination.
                    Try
                        bulkCopy.WriteToServer(readerHeader)
                    Catch ex As Exception
                        Console.WriteLine(ex.Message)
                    Finally
                        readerHeader.Close()
                    End Try

                    ' Set up the order details destination.
                    bulkCopy.DestinationTableName = "dbo.BulkCopyDemoOrderDetail"

                    ' Clear the ColumnMappingCollection.
                    bulkCopy.ColumnMappings.Clear()

                    ' Add order detail column mappings.
                    bulkCopy.ColumnMappings.Add("SalesOrderID", "SalesOrderID")
                    bulkCopy.ColumnMappings.Add("SalesOrderDetailID", "SalesOrderDetailID")
                    bulkCopy.ColumnMappings.Add("OrderQty", "OrderQty")
                    bulkCopy.ColumnMappings.Add("ProductID", "ProductID")
                    bulkCopy.ColumnMappings.Add("UnitPrice", "UnitPrice")

                    ' Write readerDetail to the destination.
                    Try
                        bulkCopy.WriteToServer(readerDetail)
                    Catch ex As Exception
                        Console.WriteLine(ex.Message)
                    Finally
                        readerDetail.Close()
                    End Try
                End Using

                ' Perform a final count on the destination tables
                ' to see how many rows were added.
                Dim countEndHeader As Long = System.Convert.ToInt32( _
                  countRowHeader.ExecuteScalar())
                Console.WriteLine("{0} rows were added to the Header table.", _
                  countEndHeader - countStartHeader)
                Dim countEndDetail As Long = System.Convert.ToInt32( _
                   countRowDetail.ExecuteScalar())
                Console.WriteLine("{0} rows were added to the Detail table.", _
                    countEndDetail - countStartDetail)

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

    Private Function GetConnectionString() As String
        Throw New NotImplementedException()
    End Function
End Module

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