Question

I am facing an issue regarding EF code first version while mapping one entity to multiple tables in existing database.

Table1: (primaryKey is IdDocument)
----------------------------
IdDocument | CreationDate
----------------------------

Table 2: (primaryKey is on IdDocument and StartDate)
------------------------------------------------------------
IdDocument | StartDate | Label | LastUpdate 
------------------------------------------------------------

In single entity, i was trying to update the information in database. Following is the entity classes.

public abstract class DocumentBase
{
    [Column("idDocument")]
    public int? IdDocument { get; set; }
    [Column("CreationDate")]
    public DateTime CreationDate { get; set; }
}

public class Document : DocumentBase
{
    [Column("startDate")]
    public DateTime StartDate { get; set; }
    [Column("lastUpdate")]
    public DateTime LastUpdate { get; set; }
    [Column("label")]
    public string Label { get; set; }
}

Following is the DbModelBuilder for the same entity,

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<Document>()
      .Map(m =>
           {
             m.Properties(document => new
                          {
                           document.IdDocument,
                           document.CreationDate
                          });
             m.ToTable("MetaDocument");
           }).Map(m =>
                  {
                   m.Properties(document => new
                                {
                                 document.IdDocument,
                                 document.StartDate,
                                 document.EndDate,
                                 document.Label,
                                 document.LastUpdate,
                                 document.Currency
                                });
                   m.ToTable("Document");
                  }).HasKey(key => new
                            {
                             key.IdDocument, key.StartDate
                            });
    base.OnModelCreating(modelBuilder);
}

It was failing to update the Table1.

Answer 1

It is not possible to map inheritance if they don’t have same primary key in all tables. If you want to map those tables to the same entity there must be one-to-one relation. It means the DocumentId in the second table must be unique and thus including StartDate in the key doesn’t make sense.

Also TPC inheritance is mapped differently.