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Mapping to Single Entity when having Many relationsship

Martin F

20 Jun, 2010 10:33 PM via web

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Hello,

i have 2 entities - Member and Email, which have corresponding tables (Members and Emails)

The Emails table contains the following columns - Id, MemberId, ValidationCode, Address, CreatedAt, ValidatedAt

If a user wants to change his Email address a new row is inserted into the Emails table, and when Validated (ValidatedAt is set to the current date), it should become "active" and available through the Member entity.

Basically the Member entity should hold a reference to the most recent validated Email.

But how can i map this ?

I dont want a List property with all Emails relating to the Member, but only 1 Email entity - which is found by the most recent validated email (validatedAt not null and order by ValidatedAt)

Martin :)

1. 2 Posted by Martin on 25 Jun, 2010 12:10 PM

   

   Anyone have an idea of how it can be done ?

   The table structure looks like this

   Members

   Id
   FirstName
   LastName

   Emails

   Id
   Address
   ValidationCode
   ValidatedAt
   MemberId

   My entities looks something like this

   public class Member
   {
       public virtual Email Email { get; set; }
   
       public virtual String FirstName { get; set; }
       public virtual String LastName { get; set; }
   }
   
   public class Email
   {
       public virtual Member Member { get; set; }
   
       public virtual String Address { get; set; }
       public virtual String ValidationCode { get; set; }
       public virtual DateTime ValidatedAt { get; set; }
   }
   

   I want the Email property on Member to map to an instance of Email where ValidatedAt is not null and ordered by ValidatedAt (so the most recent validated email is mapped).

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2. Support Staff 3 Posted by Paul Batum on 28 Jun, 2010 10:59 AM

   

   The best option I can think of is to use a one-to-many of emails, make it
   private, map it with a where clause like:

     .Where("EmailID IN (SELECT TOP 1 EmailID FROM Email Where Email.MemberID =
   _memberid ORDER BY ValidatedAt Desc)");

   and then publicly expose the returned email in the list as a single
   reference.

   Have you tried asking on the nhibernate
   users<http://groups.google.com/group/nhusers/> mailing
   list? Your question is more about NH usage than the FNH mappings.

   (I haven't tested the above SQL, but I think something like that should
   work)

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