Each LINQ to SQL datacontext we instantiate holds its own identity map (based on Martin Fowlers Identity Map Pattern). This is basically a dictionary with identity keys pointing to entities in memory previously retrieved from the database – within the scope of the datacontext, that is. More…
Adding associated / related entities with LINQ to SQL is a breeze. In the snippet below we add a new TaskList with a new Task (‘Refactor’) for a specific Employee. LINQ to SQL keeps track of the associations and adds them as expected. More…
Quick snippet below as a reminder of the most basic CUD operations in LINQ to SQL. We insert new entities with InsertOnSubmit on the specific entity collection in the datacontext. We delete existing entities the same way with the use of DeleteOnSubmit. More…
We use a XML namespace to avoid name conflicts. With a namespace we can more specifically point to an element in a XML structure. In LINQ to XML a namespace is represented by the XNamespace class. In the code snippet below we simply add a fictive namespace to the list of cars we created in the previous example. More…
In the System.Xml.Linq namespace we find a lot of handy classes for creating and manipulating XML structures and files. XDocument respresents a complete XML structure with nodes (XNode) being elements (XElement) having attributes (XAttribute). More…
It’s sometimes not possible to use LINQ to query to a database or for some reason we want to execute a SQL query statement from within our code. That’s possible by using the DataContext ExecuteQuery or ExecuteCommand methods. More…
With LINQ to SQL we can get model inheritance with filtered mapping, called Single Table Inheritance. We do this by applying a discriminator value to the derived classes. By mapping this value LINQ to SQL knows to instantiate the appropriate base or derived class. More…
By default LINQ to SQL is lazy. It defers loading of data until the very first moment it is needed by your application. This behavior makes it possible to keep adding peaces to our query until we are ready to fire a SQL statement to the database. More…