Contact me if you have any problem or question. (email: cebiyevferhad@hotmail.com)

You can check the code-project article for reading and downloading a step-by-step sample project demonstration. (http://www.codeproject.com/Articles/1131322/Automatically-Define-the-State-of-All-Entities-in)

NuGet Packages

Install-Package EntityGraphOperations

The problem – Tons of repetitive code segments

Usually we find ourselves writing very similar codes for defining the state of entities. Normally, the procedure is as follows:

Determine which properties are needed for defining existence of the entity in the database (this could be primary key properties or unique key properties).
If the result is null then the entity must be inserted.
If the result is not null and if a change has occurred in any part of the entity, then the entity must be updated.
If we have a collection of entities, then we need to compare it with the ones in the database and delete those which do not exist in the collection anymore.

and so on …

Additional explanation about why sometimes we need unique key properties in addition to the primary key properties

Say we have Phone entity which has some properties: ID, Digits, Prefix …

ID is auto-generated primary key. We do not want to insert same phone number to the table with a different ID. So Digits and Prefix properties are unique together. This situation is forcing us to take into consideration the followings:

If Id is 0, and there is not any corresponding entity in the database with the specified Digits and prefix, then it must be inserted. Otherwise, if a change has occurred, then it must be updated and so on…

Now, let’s do the same things all over again for a different entity graph. Again, and again…

The solution – Use EntityGraphOperations for Entity Framework Code First

Features:

Automatically define state of all entities
Update only those entities which have changed
Fluent API style mapping of special entity configurations
Let the user manually manage graph after automatically determining state of all entities

The example:

Let’s say I have got a Person object. Person could have many phones, a Document and he/she could have a spouse.

public class Person
{
     public int Id { get; set; }
     public string FirstName { get; set; }
     public string LastName { get; set; }
     public string MiddleName { get; set; }
     public int Age { get; set; }
     public int DocumentId {get; set;}
   
     public virtual ICollection<Phone> Phones { get; set; }
     public virtual Document Document { get; set; }
     public virtual PersonSpouse PersonSpouse { get; set; }
}

I want to determine the state of all entities which are included in the graph.

context.InsertOrUpdateGraph(person)
       .After(entity =>
       {
            // Delete missing phones.
            entity.HasCollection(p => p.Phones)
               .DeleteMissingEntities();
               
            // Delete if spouse is not exist anymore.
            entity.HasNavigationalProperty(m => m.PersonSpouse)
                  .DeleteIfNull();
       });

Also as you remember unique key properties could play role while defining the state of Phone entity. For such special purposes we have ExtendedEntityTypeConfiguration<> class, which inherits from EntityTypeConfiguration<>. If we want to use such special configurations then we must inherit our mapping classes from ExtendedEntityTypeConfiguration<>, rather than EntityTypeConfiguration<>. For example:

public class PhoneMap: ExtendedEntityTypeConfiguration<Phone>
    {
        public PhoneMap()
        {
             // Primary Key
             this.HasKey(m => m.Id);
              …
             // Unique keys
             this.HasUniqueKey(m => new { m.Prefix, m.Digits });
        }
    }