Using Transient Properties

The purpose of this topic is to show you how to configure transient properties. Transient properties are properties that will not have corresponding database representation. There are two ways in which to configure transient properties:

• You could explicitly mark the property as transient by using the AsTransient method.
• Configure partially mapped models

Explicitly marking a property as transient

The following example demonstrates how to configure the LastName property of the Person class as transient. When you update your database to the latest model state, a column for the LastName property won't be created.

MappingConfiguration<Person> personConfiguraiton = new MappingConfiguration<Person>();
personConfiguraiton.MapType().ToTable( "People" );
personConfiguraiton.HasProperty( p => p.Id ).IsIdentity();

personConfiguraiton.HasProperty( p => p.LastName ).AsTransient();

Dim personConfiguraiton As New MappingConfiguration(Of Person)()
personConfiguraiton.MapType().ToTable("People")
personConfiguraiton.HasProperty(Function(p) p.Id).IsIdentity()
personConfiguraiton.FieldNamingRules.AddPrefix = "_"

personConfiguraiton.HasProperty(Function(p) p.LastName).AsTransient()

Configuring partially mapped models

The second way is to configure partially mapped models. For this approach, you have to use explicit mapping configuration. When you update your database to the latest model state, the LastName and Address columns will be skipped.

MappingConfiguration<Person> personConfiguraiton = new MappingConfiguration<Person>();
personConfiguraiton.MapType( p => new
{
   Id = p.Id,
   FirstName = p.FirstName
} ).ToTable( "People" );
personConfiguraiton.HasProperty( p => p.Id ).IsIdentity();

Dim personConfiguraiton As New MappingConfiguration(Of Person)()
personConfiguraiton.MapType(Function(p) New With {Key .Id = p.Id,
              Key .FirstName = p.FirstName}).ToTable("People")
personConfiguraiton.HasProperty(Function(p) p.Id).IsIdentity()
personConfiguraiton.FieldNamingRules.AddPrefix = "_"

Person Class

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

Public Class Person
    Private _id As Integer
    Public Property Id() As Integer
        Get
            Return _id
        End Get
        Set(ByVal value As Integer)
            _id = value
        End Set
    End Property

    Private _firstName As String
    Public Property FirstName() As String
        Get
            Return _firstName
        End Get
        Set(ByVal value As String)
            _firstName = value
        End Set
    End Property

    Private _lastName As String
    Public Property LastName() As String
        Get
            Return _lastName
        End Get
        Set(ByVal value As String)
            _lastName = value
        End Set
    End Property

    Private _address As String
    Public Property Address() As String
        Get
            Return _address
        End Get
        Set(ByVal value As String)
            _address = value
        End Set
    End Property
End Class