Question

Let’s say I have a Company table and a Division table. Each Division has a Foreign key to a company so each company can have many Division children.

If I grab a Company object with Linq-to-sql I have a access to it’s Divisions property, a entity set of Division objects. If I add a new Division object to it and call SubmitChanges() won’t it automatically go into the Division table or am I forced to call InsertOnSubmit?

Answer 1

There are multiple ways to insert objects into the database with LINQ to SQL. For instance:

db.Divisions.InsertOnSubmit(new Division()
{
    Company = db.Company.Single(c => c.Id == 1),
    // other properties
});

db.SubmitChanges();

Or:

var company = db.Company.Single(c => c.Id == 1);

company.Divisions.Add(new Division()
{
    // other properties
});

db.SubmitChanges();

As you can see, you can use the InsertOnSubmit of the Table<Division> Divisions property on the data context, but you can also use the Add method of the EntitySet<Division> Divisions property on the Company entity. They both do -about- the same. Nice about the latter approach is that you don’t need to ‘link’ the company to the new division, because LINQ to SQL can figure that out for you.

I hope this answers your question.