SqlBulkCopyColumnMapping Class

Definition

定义 SqlBulkCopy 实例的数据源中的列与该实例的目标表中的列之间的映射。Defines the mapping between a column in a SqlBulkCopy instance's data source and a column in the instance's destination table.

public ref class SqlBulkCopyColumnMapping sealed
public sealed class SqlBulkCopyColumnMapping
type SqlBulkCopyColumnMapping = class
Public NotInheritable Class SqlBulkCopyColumnMapping
Inheritance
SqlBulkCopyColumnMapping

Examples

下面的示例将数据从AdventureWorks示例数据库中的源表大容量复制到同一个数据库中的目标表。The following example bulk copies data from a source table in the AdventureWorks sample database to a destination table in the same database. 尽管目标中的列数与源中的列数匹配,并且每个目标列与相应的源列处于相同的序号位置,但列名称不匹配。Although the number of columns in the destination matches the number of columns in the source, and each destination column is in the same ordinal position as its corresponding source column, the column names do not match. SqlBulkCopyColumnMapping 对象用于创建大容量复制的列映射。SqlBulkCopyColumnMapping objects are used to create a column map for the bulk copy.

Important

除非已按照大容量复制示例设置中所述创建了工作表,否则此示例将不会运行。This sample will not run unless you have created the work tables as described in Bulk Copy Example Setup. 提供此代码是为了演示仅使用 SqlBulkCopy 时的语法。This code is provided to demonstrate the syntax for using SqlBulkCopy only. 如果源表和目标表位于同一个 SQL Server 实例中,则使用 Transact-sql INSERT … SELECT 语句复制数据会更加简单快捷。If the source and destination tables are in the same SQL Server instance, it is easier and faster to use a Transact-SQL INSERT … SELECT statement to copy the data.

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 by name.
                SqlBulkCopyColumnMapping mapID =
                    new SqlBulkCopyColumnMapping("ProductID", "ProdID");
                bulkCopy.ColumnMappings.Add(mapID);

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

                SqlBulkCopyColumnMapping mapMumber =
                    new SqlBulkCopyColumnMapping("ProductNumber", "ProdNum");
                bulkCopy.ColumnMappings.Add(mapMumber);

                // 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 by name.
                Dim mapID As New _
                  SqlBulkCopyColumnMapping("ProductID", "ProdID")
                bulkCopy.ColumnMappings.Add(mapID)

                Dim mapName As New _
                 SqlBulkCopyColumnMapping("Name", "ProdName")
                bulkCopy.ColumnMappings.Add(mapName)

                Dim mapMumber As New _
                 SqlBulkCopyColumnMapping("ProductNumber", "ProdNum")
                bulkCopy.ColumnMappings.Add(mapMumber)

                ' 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

Remarks

列映射定义数据源和目标表之间的映射。Column mappings define the mapping between data source and the target table.

如果未定义映射(即,ColumnMappings 集合为空),则根据序号位置隐式映射列。If mappings are not defined - that is, the ColumnMappings collection is empty - the columns are mapped implicitly based on ordinal position. 对于这种方式,源架构和目标架构必须匹配。For this to work, source and target schemas must match. 否则,会引发 InvalidOperationExceptionIf they do not, an InvalidOperationException will be thrown.

如果 ColumnMappings 集合不为空,则必须指定数据源中存在的每一列。If the ColumnMappings collection is not empty, not every column present in the data source has to be specified. 被忽略的不是由集合映射的。Those not mapped by the collection are ignored.

可以按名称或序号引用源列和目标列。You can refer to source and target columns by either name or ordinal. 你还可以在同一映射集合中混合按名称和按顺序的列引用。You can also mix by-name and by-ordinal column references in the same mappings collection.

Constructors

SqlBulkCopyColumnMapping()

用于初始化新的 SqlBulkCopyColumnMapping 对象的无参数构造函数。Parameterless constructor that initializes a new SqlBulkCopyColumnMapping object.

SqlBulkCopyColumnMapping(Int32, Int32)

创建新的列映射,并使用列序号引用源列和目标列。Creates a new column mapping, using column ordinals to refer to source and destination columns.

SqlBulkCopyColumnMapping(Int32, String)

创建新的列映射,并使用列序号引用源列和目标列的列名称。Creates a new column mapping, using a column ordinal to refer to the source column and a column name for the target column.

SqlBulkCopyColumnMapping(String, Int32)

创建新的列映射,并使用列名称引用源列和目标列的列序号。Creates a new column mapping, using a column name to refer to the source column and a column ordinal for the target column.

SqlBulkCopyColumnMapping(String, String)

创建新的列映射,并使用列名称引用源列和目标列。Creates a new column mapping, using column names to refer to source and destination columns.

Properties

DestinationColumn

正在目标数据库表中映射的列的名称。Name of the column being mapped in the destination database table.

DestinationOrdinal

目标表中目标列的序号值。Ordinal value of the destination column within the destination table.

SourceColumn

正在数据源中映射的列的名称。Name of the column being mapped in the data source.

SourceOrdinal

数据源中源列的序号位置。The ordinal position of the source column within the data source.

Methods

Equals(Object)

确定指定的对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode()

作为默认哈希函数。Serves as the default hash function.

(Inherited from Object)
GetType()

获取当前实例的 TypeGets the Type of the current instance.

(Inherited from Object)
MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(Inherited from Object)
ToString()

返回表示当前对象的字符串。Returns a string that represents the current object.

(Inherited from Object)

Applies to

See also