BulkInsertMapItem

This class is used to define a mapping of the source and destination columns when doing the bulk operations (i.e.: BulkDelete, BulkInsert, BulkMerge and BulkUpdate).

Create a new Instance

Below is simple way to create an instance.

var mapItem = new BulkInsertMapItem("SourceId", "DestinationId");

Usage for BulkOperations

Let us say you a model class like below.

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
    public string CreatedDate { get; set; }
}

And you have a table structure like below.

CREATE TABLE [dbo].[Person]
(
    [Id] [bigint] IDENTITY(1,1) NOT NULL,
    [Name] [nvarchar](128) NOT NULL,
    [Age] [int] NOT NULL,
    [CreatedDateUtc] [datetime2](5) NOT NULL,
    CONSTRAINT [CRIX_Person_Id] PRIMARY KEY CLUSTERED ([Id] ASC) ON [PRIMARY]
)
ON [PRIMARY];
GO

Then, you created a method that does return an array of your model.

private IEnumerable<Person> GetPeople(int count = 10)
{
    for (var i = 0; i < count; i++)
    {
        yield return new Person
        {
            FirstName = $"FirstName{i}",
            LastName = $"LastName{i}",
            Age = i,
            CreatedDateUtc = DateTime.UtcNow
        };
    }
}

Then, you can do BulkInsert with the mappings below.

using (var connection = new SqlConnection(connectionString))
{
    var mappings = new []
    {
        new BulkInsertMapItem("FirstName", "FName"),
        new BulkInsertMapItem("LastName", "LName"),
        new BulkInsertMapItem("Age", "Age")
        new BulkInsertMapItem("CreatedDate", "CreatedDateUtc")
    };
    var people = GetPeople(100000);
    connection.BulkInsert(people, mappings: mappings);
}

You can also do the same for (i.e.: BulkDelete, BulkMerge and BulkUpdate). Please also be reminded that the mappings argument are not mandatory. Leaving this blank would make the bulk operations auto-map the columns based on the equality of the source and destination column-names (case-insensitive).