Linq-To-SQL Problem Inserting Multiple Objects That Are The Same

Question

Here is my object association:

Summary
-> Job
  -> Operator
-> Job
  -> Operator

So, I have a Summary object that contains a collection of Jobs, which has an Operator object (clock #, name, etc)

When creating a new summary, I go through and create the new jobs that exist and add all the properties. Then, do a single insert on the Summary object that is built. Then, this inserts new jobs and operators if needed, otherwise I may read existing Jobs and Operators from the database.

The problem comes in when I have the same Operator running both Jobs and that Operator does not exist in the database. Linq-To-SQL is trying to insert the same object twice and failing since I'm using the clock # as the primary key.

I can create an auto number for the primary key, but then I'll have duplilcate data and I'd rather not do that. Does anyone have any ideas to get around this?

Thanks!

New problem...when I try to insert the operator during the creation of the summary's child objects (through a loop), Linq tries to submit all changes (including the partially built summary). There are some date fields that are not populated which are causing the insert to crash. Also, I'm using StructureMap to cache the db so the different repositories should be using the same instance. — Dragn1821
– Dragn1821, Commented Jun 24, 2010 at 18:27

Matteo Mosca · Accepted Answer · 2010-06-24 12:29:07Z

1

I think the problem resides in how you write your object creation. I haven't seen your code, but I think you're doing something like this:

Summary summary = new Summary
                                  {
                                      Jobs = new List<Job>
                                                 {
                                                     new Job
                                                         {
                                                             Operator = new Operator {Name = "foo"}
                                                         },
                                                     new Job
                                                         {
                                                             Operator = new Operator {Name = "foo"}
                                                         }
                                                 }
                                  };

If that's your case, try instantiating the operator "foo" beforehand and then assigning it to both jobs.

If you already do it and still get the error, then you should create the operator before and save it to the database, then retrieve it and assign it to the desired jobs.

answered Jun 24, 2010 at 12:29

Matteo Mosca

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2 Comments

Dragn1821 Over a year ago

Yes, it is similar to that. The only difference is where you create the new Operator, I would do a check with the db first and pull from there if it exists. I had thought of your solution, but I'm worried its going to take alot of time to rewrite what we've already built. Was hoping there would be a simple property I could turn on and Linq would check for this kind of thing...

Dragn1821 Over a year ago

Ended up having to do a check when adding the new operator to see if there are more than one jobs...if so, and the operator's are the same, then set the operator object within the 2nd job to the value of the operator object in the first job (instead of creating a new operator for the 2nd job). Seems to work.

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