Sql – Linq2SQL related records

asp.net-mvclinq-to-sql

I'm sure this has been answered but I can't find it.

Say I have three tables;

Projects

Id <= unique key
name

Attributes

Id <= unique key
Name

ProjectAttributes

id <= unique key
ProjectId
AttributeId

I'm using a dbml file and I have all the associations drawn up within the dbml.

So how in my view, do I itterate through all the Attributes for the project.

I thought;

<% foreach (Project project in Model){%>
    <% foreach (Repository.Attribute attr in project.ProjectAttributes ) { %>

but that clearly doesn't work.

So how, given a project, do I get all the attributes associated to it?

Best Answer

Many to many associations in L2S are always done including the foreign key table, so it should probably be:

<% foreach (Project project in Model){%>
    <% foreach (ProjectAttribute attr in project.ProjectAttributes ) { %>

And attr.Attribute will then be your needed attribute

Related Solutions

Sql – LINQ to SQL not recognizing new associations

Check your Error List page. You might have something like the following in there:

DBML1062: The Type attribute '[ParentTable]' of the Association element 'ParentTable_ChildTable' of the Type element 'ChildTable' does not have a primary key. No code will be generated for the association.

In which case all you should need to do is make sure that both tables have a primary key set and re-save the dbml file. This will invoke the custom tool, which will in turn update the designer.cs file and create code for the association.

Sql – Linq2Sql Insert Records To Related Tables

You have to write it this way I think (assuming you have classes Participant and Challenge):

Participant applicant = new Participant();
Participant respondant = new Participant();
//update your participants here

Challenge insertedChallenge = new Challenge();
//update your challenge values here

applicant.Challenges.add(insertedChallenge);
respondant.Challenges1.add(insertedChallenge);

submitChanges();

Linq-to-SQL should automatically assign these properties (Challenges and Challenges) so it can set the key values for you.

Hope it helps.

Best Answer

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