Visual-studio – LINQ to SQL: Multiple / Single .dbml per project

linqlinq-to-sqlvisual studio

I've read Rick Strahl's article on Linq to SQL DataContext Lifetime Management hoping to find some answers on how I would manage my .dbml files since they are so closely related to DataContext. Unfortunately, Rick's article seems to be focused on DataContext lifetime at runtime though, and my question is concerned with how the .dbml's should be organized at design time.

The general question of 'Best practices with .dbml's' has been asked and answered here, and the answers have focused on external tools to manage the .dbml.

I'm asking a more focused question of when and why should you not have a single .dbml file in your LINQ to SQL based project?

Best Answer

Please note that LINQ2SQL is intended for simple and easy way to handle database relationship with objects.

Do not break table relationship and units of work concepts by creating multiple .dbml files.

If you ever need to create multiple .dbml files (which i don't recommend), then try to satisfy the following:-

If you create multiple databases with no relationship between those database tables.
If you want to use one of these .dbml just to handle stored procedures
If you do not care about unit of work concept.

If your database is too complex, then I would consider ORM such as NHibernate, EF 4

Related Solutions

.net – Entity Framework vs LINQ to SQL

LINQ to SQL only supports 1 to 1 mapping of database tables, views, sprocs and functions available in Microsoft SQL Server. It's a great API to use for quick data access construction to relatively well designed SQL Server databases. LINQ2SQL was first released with C# 3.0 and .Net Framework 3.5.

LINQ to Entities (ADO.Net Entity Framework) is an ORM (Object Relational Mapper) API which allows for a broad definition of object domain models and their relationships to many different ADO.Net data providers. As such, you can mix and match a number of different database vendors, application servers or protocols to design an aggregated mash-up of objects which are constructed from a variety of tables, sources, services, etc. ADO.Net Framework was released with the .Net Framework 3.5 SP1.

This is a good introductory article on MSDN: Introducing LINQ to Relational Data

C# – the syntax for an inner join in LINQ to SQL

It goes something like:

from t1 in db.Table1
join t2 in db.Table2 on t1.field equals t2.field
select new { t1.field2, t2.field3}

It would be nice to have sensible names and fields for your tables for a better example. :)

Update

I think for your query this might be more appropriate:

var dealercontacts = from contact in DealerContact
                     join dealer in Dealer on contact.DealerId equals dealer.ID
                     select contact;

Since you are looking for the contacts, not the dealers.

Best Answer

Related Solutions

.net – Entity Framework vs LINQ to SQL

C# – the syntax for an inner join in LINQ to SQL

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