![]() In the first example, we only query the three fields we need: var blogPosts db.BlogPosts.Select (b > new BlogPostModel (b.Title, b.Url, b.DatePublished)).ToList () Note that because we use a projection, EF does not track any entity and the use of AsNoTracking is not. entity Mapper.Map (model, entity) Otherwise, your entity instance is overwritten with a new instance, and you lose the entity created in the first line. The solution is to use a view model with a projection.For reference navigation properties, use dotted paths, and for collection navigation properties, use the Select operator. Try passing entity as a second parameter to your mapping. A relational database deals with related data. This is also useful when we migrate from existing applications. This approach is useful when we work with an existing database. ![]() In this approach, we create our database first. When I use LinqPad to perform this query, I encounter the following error, which I do not understand:ĪrgumentException: A navigation property specified on the type must be referred to in the Include path expression. In this article, weâll take a look at the EF Core Database-First approach. This is my Linq statement: Tasks.Where(t => t.AccessLevel tl.TaskLinks.Where(tl2=> tl2.IfInactive = false) But in order to exclude any Inactive (bool) records, I need to filter the Task (by Access Level int) and the TaskLinks. Suppose you work with an ORM (e.g.: Entity Framework) and you usually use DTO ( Data Transfer Object) pattern to transfer data. I'm attempting to choose the task, eager load the TaskLinks (via.Include), and choose the Entity associated with the TaskLink. ![]() I have a Linq query that looks up information from the following tables: tasks with a many-to-one relationship to: A table called Entities is linked directly to TaskLinks and TaskLinks.
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