SqlBulkCopyColumnOrderHintCollection.Remove Metode

Definisi

Ruang nama:

Microsoft.Data.SqlClient

Rakitan:

Microsoft.Data.SqlClient.dll

Paket:

Microsoft.Data.SqlClient v5.2.0

Menghapus elemen yang ditentukan SqlBulkCopyColumnOrderHint dari SqlBulkCopyColumnOrderHintCollection.

public:
 void Remove(Microsoft::Data::SqlClient::SqlBulkCopyColumnOrderHint ^ columnOrderHint);

public void Remove(Microsoft.Data.SqlClient.SqlBulkCopyColumnOrderHint columnOrderHint);

member this.Remove : Microsoft.Data.SqlClient.SqlBulkCopyColumnOrderHint -> unit

Public Sub Remove (columnOrderHint As SqlBulkCopyColumnOrderHint)

Parameter

columnOrderHint

SqlBulkCopyColumnOrderHint

SqlBulkCopyColumnOrderHint objek yang akan dihapus dari koleksi.

Pengecualian

ArgumentNullException

Nilainya null.

Contoh

Contoh berikut melakukan dua operasi penyalinan massal. Operasi pertama menyalin informasi header pesanan penjualan, dan yang kedua menyalin detail pesanan penjualan. Contoh menentukan petunjuk urutan kolom untuk kolom OrderDate dalam operasi salin massal pertama. Petunjuk dihapus sebelum operasi penyalinan massal kedua.

Penting

Sampel ini tidak akan berjalan kecuali Anda telah membuat tabel kerja seperti yang dijelaskan dalam Penyiapan Contoh Salinan Massal. Kode ini disediakan untuk mendemonstrasikan sintaks untuk menggunakan SqlBulkCopy saja. Jika tabel sumber dan tujuan berada dalam instans SQL Server yang sama, lebih mudah dan lebih cepat untuk menggunakan pernyataan Transact-SQL INSERT … SELECT untuk menyalin data.

using System;
using System.Data;
using Microsoft.Data.SqlClient;

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

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

            // Perform an initial count on the destination
            //  table with matching columns. 
            SqlCommand countRowHeader = new SqlCommand(
                "SELECT COUNT(*) FROM dbo.BulkCopyDemoOrderHeader;",
                connection);
            long countStartHeader = 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. 
            SqlCommand countRowDetail = new SqlCommand(
                "SELECT COUNT(*) FROM dbo.BulkCopyDemoOrderDetail;",
                connection);
            long countStartDetail = System.Convert.ToInt32(
                countRowDetail.ExecuteScalar());
            Console.WriteLine(
                "Starting row count for Detail table = {0}",
                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 SqlCommand(
                "SELECT [SalesOrderID], [OrderDate], " +
                "[AccountNumber] FROM [Sales].[SalesOrderHeader] " +
                "WHERE [AccountNumber] = @accountNumber;",
                connection);
            SqlParameter parameterAccount = new SqlParameter();
            parameterAccount.ParameterName = "@accountNumber";
            parameterAccount.SqlDbType = SqlDbType.NVarChar;
            parameterAccount.Direction = ParameterDirection.Input;
            parameterAccount.Value = "10-4020-000034";
            headerData.Parameters.Add(parameterAccount);
            SqlDataReader readerHeader = headerData.ExecuteReader();

            // Get the Detail data in a separate connection.
            using (SqlConnection connection2 = new SqlConnection(connectionString))
            {
                connection2.Open();
                SqlCommand sourceDetailData = 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);

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

                // Create the SqlBulkCopy object. 
                using (SqlBulkCopy bulkCopy =
                           new SqlBulkCopy(connectionString))
                {
                    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");

                    // Add the order hint for the OrderDate column.
                    SqlBulkCopyColumnOrderHint hintDate =
                        new SqlBulkCopyColumnOrderHint("OrderDate", SortOrder.Ascending);
                    bulkCopy.ColumnOrderHints.Add(hintDate);

                    // 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");

                    // Remove the order hint for the OrderDate column.
                    bulkCopy.ColumnOrderHints.Remove(hintDate);

                    // 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 = System.Convert.ToInt32(
                    countRowHeader.ExecuteScalar());
                Console.WriteLine("{0} rows were added to the Header table.",
                    countEndHeader - countStartHeader);
                long countEndDetail = 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();
            }
        }
    }

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

Keterangan

Metode Hapus paling umum digunakan saat Anda menggunakan satu SqlBulkCopy instans untuk memproses lebih dari satu operasi penyalinan massal. Jika Anda membuat petunjuk urutan kolom untuk satu operasi penyalinan SqlBulkCopyColumnOrderHintCollection massal, Anda harus menghapus setelah WriteToServer metode dan sebelum memproses salinan massal berikutnya.

Anda dapat menghapus seluruh koleksi dengan menggunakan Clear() metode , atau menghapus petunjuk satu per satu menggunakan metode Hapus atau RemoveAt metode .

Melakukan beberapa salinan massal menggunakan instans yang sama SqlBulkCopy biasanya akan lebih efisien dari sudut pandang performa daripada menggunakan terpisah SqlBulkCopy untuk setiap operasi.