table-per-type

I'm trying to convert an xml Entity Framework model to Code First (CTP5) one. I have to model a hierarchy which fits quite well the TPT pattern. The only problem I have is that the primary key/foreign key of the "inheriting" table has a different name from the primary key of the base class. These are the relevant fields of the involved tables CREATE TABLE site.Domains ( ID INT NOT NULL PRIMARY KEY, Domain NVARCHAR(128) NOT NULL ) CREATE TABLE site.MainSites ( FKDomainID INT NOT NULL PRIMARY KEY REFERENCES site.Domains(ID) ) CREATE TABLE site.SisterSites ( FKDomainID INT NOT NULL PRIMARY KEY

I want to use the EF (4.2) in the following scenario: There exists a database already (so I chose the database-first approach) and it is a SQL Anywhere DB. I want to use persistence-ignorant business objects, so I use the DbContext Template to generate POCO classes from the EDM. There is one simple inheritance hierarchy among my entities: an abstract base entity and two concrete derived entities. In the database there is one table for each type of the inheritance hierarchy (Table-Per-Type Strategy). Each of these three tables has a primary key column ( Id , type: integer ), and the association

I want to create a TPT mapping where the base class itself holds information and the derived classes just extend it. Basically, I've got a base class, and a few derived classes, and I'm wondering how to handle their mapping. Here's a ridiculously simplified example: [Table("Task")] public class Task : TaskBase { // No properties... This is just a "Task", not either an internal nor external one. } [Table("InternalTask")] public class InternalTask : TaskBase { public int UserId { get; set; } public virtual User User { get; set; } } [Table("ExternalTask")] public class ExternalTask : TaskBase {

So it turns out that I am the last person to discover the fundamental floor that exists in Microsoft's Entity Framework when implementing TPT (Table Per Type) inheritance. Having built a prototype with 3 sub classes, the base table/class consisting of 20+ columns and the child tables consisting of ~10 columns, everything worked beautifully and I continued to work on the rest of the application having proved the concept. Now the time has come to add the other 20 sub types and OMG, I've just started looking the SQL being generated on a simple select, even though I'm only interested in accessing

I have a simple hierarchy public abstract class CommunicationSupport { public SupportTypeEnum Type { get; set; } public Country Origin { get; set; } // National or Foreign support } public class TelecomSupport : CommunicationSupport { public string Number { get; set; } } public class PostalSupport : CommunicationSupport { public Address Address { get; set; } } I plan to use the Table-per-type hierarchy for my DB. So 3 tables will be created, one base and two child using the same PK as the base. My problem is that I want to be able to update a CommunicationSupport by changing it's type. Let's

I have this class hierarchy in code: [Table("A")] public class A : IIdentification { public int id { get; set; } } [Table("B")] public class B : A { //some properties here public Aid { get; set;} ForeignKey("Aid"); public A A { get; set; } } [Table("C")] public class C : B { //some properties here public Bid { get; set; } ForeignKey("Bid"); public B B { get; set; } } [Table("D")] public class D : C { public Cid { get; set;} ForeignKey("Cid"); public C C { get; set; } } How can I make one table with a foreign key for each class or any other possible correct way? Maybe someone could post some