LINQ to SQL not recognizing new associations?

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I have two projects using legacy databases with no associations between the tables. In one, if I create associations in the DBML file, I can reference the associations in LINQ like this:

From c In context.Cities Where c.city_name = "Portland" _
Select c.State.state_name

(assuming I added the link from City.state_abbr to State.state_abbr in the DBML file.)

In a different project that uses a different database, adding the association manually doesn't seem to give me that functionality, and I'm forced to write the LINQ query like this:

From c In context.Cities Where c.city_name = "Portland" _
Join s In context.States On c.state_abbr = s.state_abbr _
Select s.state_name

Any idea what I could be missing in the second project?

Note: These are completely contrived examples - the real source tables are nothing like each other, and are very cryptic.

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.

Programming Microsoft LINQ in .NET Framework 4, In the O/R Designer, you can define associations between entities in two you can link two entities to define an association that might or might not have a relationship that corresponds to an association defined between LINQ to SQL entities. a new association by using the context menu and rightclicking an empty area  I am getting this error, i am trying to resolve it long but unable to fix it. LINQ to Entities does not recognize the method 'System.Object Parse(System.Type, System.String)' method, and this method cannot be translated into a store expression. publi

It looks like my problem was my tables didn't have primary keys in the second project. Like I stated, these are legacy tables, so I had to do the linking and primary key stuff in the Database Context instead of the database itself, and I just forgot to specify the primary keys the second time around. Frustrating when you don't spot it, but it makes sense now.

Pro LINQ Object Relational Mapping in C# 2008, <Association Name="Contact_Employee" Member="Contact" Int32" DbType="​Int NOT NULL" IsPrimaryKey="true" CanBeNull="false" /> <Column Additionally​, new association properties and attributes have been added to the classes, and a few In the properties that 62 CHAPTER 3 □ INTRODUCTION TO LINQ TO SQL. In a different project that uses a different database, adding the association manually doesn't seem to give me that functionality, and I'm forced to write the LINQ query like this: From c In context.Cities Where c.city_name = "Portland" _ Join s In context.States On c.state_abbr = s.state_abbr _ Select s.state_name

Sometimes, when everything is configured correctly but still not working, the solution can be as simple as restarting Visual Studio.

I don't know why it happens sometimes, but I thought I should add this answer because having done some searching for a solution myself, it seems nobody has suggested this yet...

Walkthrough: Querying Across Relationships (C#), In general, new applications should use the Entity Framework when an In Visual Studio, you create LINQ to SQL classes that represent SQL Editing .​dbml files with a designer surface requires the LINQ to SQL tools which are not creating LINQ to SQL entity classes and associations (relationships) that  If there are still issues with the Linq to SQL trying to convert the where condition to the underlying SQL query, the approach of using int vs. string is correct. My +5! Edson_Ferreira 1-May-14 13:31pm

LINQ to SQL O/R Designer overview, People have been asking via Twitter and the LINQ to SQL forums so 25 Aug 2009 – Updated with additional changes, some of which are new in beta 2. Foreign key property setter now checks all affected associations not just the because LinqToSql will not recognize the key value if it is not padded  This is not necessary for using LINQ to SQL, it is only done here to simplify distribution. 3. Declare your tables. Finally, represent each table* you want to connect to as a Table<T> collection of the class type that you (are about to) create for it. Normally, you might create the classes first, but let's see what this looks like.

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LINQ to SQL not generating code for association, LINQ to DB is the fastest LINQ database access library offering a simple, light, fast, and type-safe layer between However, it's not as heavy as LINQ to SQL or Entity Framework. using LinqToDB; using (var db = new DbNorthwind()) { db. Then select the "LINQ Library" project icon and create a new LINQ enabled class library: This will create a class library project whose MSBuild project file enables compilation support for LINQ. A default "Class1.cs" file is added to the project -- I recommend just deleting it to start with an empty project. Step 2: Add a LINQ for SQL Data

Comments
  • Did you ever find the answer to this? I'm having the same trouble myself...
  • Found a fix for my problem, see the answer I posted:
  • Geez I wish I had tried this sooner. I wasted about two hours trying to get this working and it was just VS being a jerk. Deleting the appData temp files and restarting VS worked for me.