# IT:AD:Code First:Entities:Classes #



* [[../|(UP)]]
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### CheckList: Classes Design ###

* MUST: Parameter less constructor
* MUST: Not be sealed or abstract
* MUST: Have a PK. 
    * Convention: Named `Id` or `<Entity>Id`
    * DataAnnotation: `[Key()]` (see [[IT/AD/Code First/Annotations/]])
    * FluentAPI:  `modelBuilder.Entity<Person>().HasKey(ma => ma.SSN);`(see [[IT/AD/Code First/FluentAPI/Properties/]])
* COULD:Table Name mapping can be forced by:
    * DataAnnotation: `[ClassName]` (see [[IT/AD/EF/Annotations/]]):
    * FluentAPI: within `DataContext.OnModelCreating()`: `modelBuilder.Entity<Invoice>().Property(i => i.Name)
  .HasColumnName("ClientInvoices");` (see [[IT/AD/Code First/FluentAPI/]]):
        * Note: For more complex mapping: [http://bit.ly/tjUwK8](http://bit.ly/tjUwK8)
* CONSIDER: You can exclude entities:
    * DataAnnotation: `[NotMapped]` (see [[IT/AD/Code First/DataAnnotations/]])
    * FluentAPI: within `DataContext.OnModelCreating()`: `modelBuilder.Ignore<Invoice>()` (see [[IT/AD/Code First/FluentAPI/]])
Example:

`modelBuilder.Entity<X>.MapSingleType().ToTable("xyxTable");`


* CONSIDER: Watch out for design flaw of making Entitities into *Anemic Entities*
    * Consider using Partial or Extension Methods to contain Domain Logic in Entities rather than forcing it to be included in the Application Layer outsider of the Domain Layer.


    * `_graphContext.Configuration.AutoDetectChangesEnabled = false;`