Entity Framework Virtual Properties and Database Access for Id Properties?

Question

I have a lot of interconnected objects in the project I'm working on, and I use WCF to use them in several client applications. Soon I realized that with every call, I serialized half the data in the database. I fixed the immediate problem, but the system still processes a lot of database queries, since service-level objects repeat all nested objects in the data layer in their constructors. Many times this is completely unnecessary, so I began to consider alternatives.

If I specify the identifier of my attached property, I do not believe that the database call will be executed unless I get access to the properties of the attached object.

public class MyDataObject
{    
    public Guid Id { get; set; }
    public string SomeProperty { get; set; }
    public Guid NestedDataObjectId { get; set; }
    [ForeignKey("NestedDataObjectId")]
    public virtual NestedDataObject NestedDataObject { get; set; }
}

Then I can use the constructor of my service object to determine whether it is lazy to load nested objects like this:

public class MyServiceObject
{
    public MyServiceObject(MyDataObject myDataObject, 
               bool includeNested = true)
    {
        Id = myDataObject.Id;
        SomeProperty = myDataObject.SomeProperty;
        NestedServiceObjectId = myDataObject.NestedDataObjectId;
        if (includeNested)
            NestedServiceObject = new NestedServiceObject(myDataObject.NestedDataObject,
                includeNested);
    }
}

Which works fine, except that now I have a problem with my db mock context for my unit tests, since I have to add an object and id to each mock DbSetwhen I change the service code to use a NestedObjectIdproperty, not a propertyNestedObject.Id

Therefore, I was wondering if the Id field is the only virtual property available to me if it still calls the database for the entire object. Sort of

if (includeNested)
{
    NestedServiceObject = new NestedServiceObject(myDataObject.NestedDataObject);
}
else
{
    NestedServiceObject = new NestedServiceObject(myDataObject.NestedDataObject.Id);
} 

, NestedObject.Id, , , , , , .

Answer 1

, API- . , , .

API , .

Request Response . , - . , , .

, . , EF , AutoMapper.

:

var result = db.Students
    .Select(x => new { Id = x.Id, FacultyName = x.Faculty.Name})
    .FirstOrDefault(x => x.Id == studentId);

- , EF , .

Answer 2

, EF . Null Reference, NestedDataObject, .

, , .

Answer 3

You can use include

.Include(x => x.myDataObject.SomeProperty)