SqlBulkCopyColumnMapping Class

Definition

Namespace:

Microsoft.Data.SqlClient

Assembly:

Microsoft.Data.SqlClient.dll

Package:

Microsoft.Data.SqlClient v5.2.0

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

Object

SqlBulkCopyColumnMapping

Examples

The following example bulk copies data from a source table in the AdventureWorks sample database to a destination table in the same database. 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 objects are used to create a column map for the bulk copy.

Important

This sample will not run unless you have created the work tables as described in Bulk Copy Example Setup. This code is provided to demonstrate the syntax for using SqlBulkCopy only. 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;
using System.Data;
using Microsoft.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 mapNumber =
                    new SqlBulkCopyColumnMapping("ProductNumber", "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;";
    }
}

Remarks

Column mappings define the mapping between data source and the target table.

If mappings are not defined - that is, the ColumnMappings collection is empty - the columns are mapped implicitly based on ordinal position. For this to work, source and target schemas must match. If they do not, an InvalidOperationException will be thrown.

If the ColumnMappings collection is not empty, not every column present in the data source has to be specified. Those not mapped by the collection are ignored.

You can refer to source and target columns by either name or ordinal. You can also mix by-name and by-ordinal column references in the same mappings collection.

Constructors

SqlBulkCopyColumnMapping()	Parameterless constructor that initializes a new SqlBulkCopyColumnMapping object.
SqlBulkCopyColumnMapping(Int32, Int32)	Creates a new column mapping, using column ordinals to refer to source and destination columns.
SqlBulkCopyColumnMapping(Int32, String)	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)	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)	Creates a new column mapping, using column names to refer to source and destination columns.

Properties

DestinationColumn	Name of the column being mapped in the destination database table.
DestinationOrdinal	Ordinal value of the destination column within the destination table.
SourceColumn	Name of the column being mapped in the data source.
SourceOrdinal	The ordinal position of the source column within the data source.