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entity-frameworkdata-modelingcode-firstentity-framework-ctp5ef-code-first

Entity Framework CTP5 (Code First) Modeling - lookup tables


Assume the following table structure:

Tables:

**Tasks**
taskID int PK
taskName varchar

**Resources**
resourceID int PK
resourceName varchar

**Assignments**
assignmentID int PK
taskID int FK
resourceID int FK

The assignments table relates a task with the resource that is assigned to it. Is it possible to map this structure with the model builder so that I do not have to create an Assignment poco class - hiding some of the underlying data structure?

I.E.:

public class Task
{
    public int taskID { get; set; }
    public string taskName { get; set; }

    public virtual ICollection<Resource> resourceItems { get; set; }
}

public class Resource
{
    public int resourceID { get; set; }
    public string resourceName { get; set; }
}

How can I use the model builder to map tasks to resources without creating an assignment poco class?


Solution

  • Here is an article about this very thing.

    Edit, I dont have an IDE in front of me so this might not be the exact "latest" syntax, but it should get you started:

    modelBuilder.Entity<Task>().HasMany(a => a.Resources).WithMany(b => b.Tasks).Map(m => 
    { 
    
      m.MapLeftKey(a => a.TaskId,"taskId");
    
      m.MapRightKey(b => b.ResourceId, "resourceId");
    
      m.ToTable("Assignments"); 
    
    });