Solved

How do you use LINQ to select foreign key fields that reside in the same foreign table?

Posted on 2010-08-16
3
477 Views
Last Modified: 2013-12-17
I am building an application that lists football matches for a tournament.  I have attachd the database diagram for further explanation.

I am trying to list all the matches in a grid but I am having difficulty retrieving the names of TeamA and TeamB from dw_Team.  TeamA and TeamB's ID's are both foreign keys in the dw_Match table.  You'll have to look at the database diagram for a cleared understanding.

The code I am currently using is only returning TeamA's name, and not team B.  Can someone help me out with the LINQ/Lamba query that I need?

Thanks in advance.
var matches = from m in db.Matches
                      orderby m.Date
                      select new
                      {
                          ID = m.ID,
                          StageName = m.Stage.Name,
                          MatchDayTitle = m.MatchDay.Title,
                          Date = m.Date,
                          Time = m.Time,
                          TeamAName = m.Team.Name,
                          TeamBName = m.Team.Name
                      };

Open in new window

Database-Diagram.PNG
0
Comment
Question by:markerasmus
  • 2
3 Comments
 
LVL 10

Accepted Solution

by:
joriszwaenepoel earned 500 total points
ID: 33445515
It looks like you have only defined 1 of the 2 relationships between Match and Team.
If you modify your database to include the 2nd relationship, then regenerate your LINQ model, then your "Match" objects should have 2 "Team" properties, one for TeamA and one for TeamB.
0
 

Author Comment

by:markerasmus
ID: 33445724
Apologies, that was just an oversight on my part.  Both relationships are setup, they were just sitting on top of each other and I hadn't dragged them apart.

But you have answered my question.  There was a m.dw_team object that I hadn't spotted that was holding a reference to TeamA.  m.Team holds the value for TeamB.

Is there a way to control those object names e.g renaming them to TeamA and TeamB, instead of the default with having to edit the datacontext.cs?  
0
 
LVL 10

Expert Comment

by:joriszwaenepoel
ID: 33445866
Are you using Linq to SQL or Entity Framework (and which version)?

I know that with EF you can change the names of the generated properties, but you might need to modify that again if you regenerate the model later.  I am not sure about LINQ to SQL.
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In my previous two articles we discussed Binary Serialization (http://www.experts-exchange.com/A_4362.html) and XML Serialization (http://www.experts-exchange.com/A_4425.html). In this article we will try to know more about SOAP (Simple Object Acces…
This article shows how to deploy dynamic backgrounds to computers depending on the aspect ratio of display
A short tutorial showing how to set up an email signature in Outlook on the Web (previously known as OWA). For free email signatures designs, visit https://www.mail-signatures.com/articles/signature-templates/?sts=6651 If you want to manage em…
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an antispam), the admini…

749 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question