entity framework 5 - One to Zero or One relationship with EF5 fluent mapping -


i have 3 entities:

public class mainentity() {     public long id { get; set; }      public long entityaid { get; set; }     public entitya optionalentitya { get; set; }      public long entitybid { get; set; }     public entityb optionalentityb { get; set; }      public string sprop { get; set; } }  public class entitya() {     public long id { get; set; }      public long mainentityid { get; set; }     public mainentity requiredentity { get; set; } }  public class entityb() {     public long id { get; set; }      public long mainentityid { get; set; }     public mainentity requiredentity { get; set; } }

all 3 entities have there own id generated database:

property(t => t.id).hasdatabasegeneratedoption(databasegeneratedoption.identity);

how can define relationship between mainentity , entitya , entityb in order have:

  • mainentity may have 0 or 1 entitya
  • mainentity may have 0 or 1 entityb
  • entitya must have 1 mainentity
  • entityb must have 1 mainentity

in mainentityconfigurationmap have defined relation this:

hasoptional(m => m.optionalentitya).withrequired(ea => ea.requiredentity); hasoptional(m => m.optionalentityb).withrequired(eb => eb.requiredentity);

looking @ generated migration have entitya:

        createtable(             "dbo.entitya",             c => new                 {                     id = c.long(nullable: false, identity: true),                     mainentityid = c.long(nullable: false),                 })             .primarykey(t => t.id)             .foreignkey("dbo.mainentity", t => t.id)             .index(t => t.id);

entity framework defining shared primary key here, there way avoid , make mainentityid poiting mainentity.id?

entity framework supports one-to-one relation on top of shared primary key (pk in dependent table fk principal table). reason fk in dependent table must unique enforce one-to-one relation ef doesn't support unique constraint (except pk).


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