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Entity Framework question

arpoarpo asked:

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Suppose you have a SQL Server database (TestDB) containing only two tables that can be created by executing the following Transact-SQL:

SQL
CREATE TABLE Person(
   personId INT PRIMARY KEY IDENTITY(1,1),
   name VARCHAR(50)
)

CREATE TABLE House(
   personId INT,
   houseId INT,
   builtDate DATETIME,
   PRIMARY KEY(personId, houseId)
)


Ideally, the field personId in the table House would be a foreign key referencing the field personId in the table Person, but as you can see, it is not. Moreover, assume the database schema CANNOT be modified.

I would like to have the following classes to represent those tables by using Entity Framework:

C#
[Table("Person")]
public class Person
{
   [Column("personId")]
   public int Id{ get; set; }
   
   [Column("name")]
   public string Name{ get; set; }

   public List<House> Houses{ get; set; }
}

[Table("House")]
public class House
{
   [Column("personId")]
   public int OwnerId { get; set; }
   
   [ForeignKey("OwnerId")] 
   public Person Owner { get; set; }
   
   [Column("houseId")]
   public int HouseId{ get; set; }
   
   [Column("builtDate")]
   public DateTime BuiltDate{ get; set; }
}

public class EFDbContext : DbContext
{
   public DbSet<Person> Persons {get; set;}

   public DbSet<House> Houses {get; set;}
}


I think this would be the model of classes that Entity Framework would generate if there were a relationship in the database between Person(personId) and House(personId), but remember there is no foreign key constraint in the database.

I think the key question is: How would you simulate having a foreign key when you actually don't have it?

Remember I cannot touch the database.

Thanks.
Tags: C#, SQL, .NET, ADO.NET, Entity Framework, Database Development

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