Question

Hello,

subject

Updated at 25.11.2009 9:20:20

Thanks, but dont work.

[HierarchyRoot]
    public class Person : Entity
    {
        [Field, Key]
        public int Id
        {
            get; private set;
        }
    }

    [HierarchyRoot]
    public class Book : Entity
    {
        [Field, Key]
        public int Id
        {
            get;
            private set;
        }
    }

    [HierarchyRoot]
    public class BookReview : Entity
    {
        [Field, Key(1)]
        public Person Reviewer { get; private set; }

        [Field, Key(0)]
        public Book Book { get; private set; }

        [Field(Length = 4096)]
        public string Text { get; set; }

        public BookReview(Book book, Person reviewer)
            : base(book, reviewer)
        { }
    }

When build domain throws exception "Default generator can serve hierarchy with exactly one key field."

This thread was imported from our support forum. The original discussion may contain more detailed answer. Original topic by Alexey Abretov.

Answer 1

Hello,

Here is the sample with multicolumn key:

[HierarchyRoot]
public class BookReview : Entity
{
  [Field, Key(1)]
  public Person Reviewer { get; private set; }

  [Field, Key(0)]
  public Book Book { get; private set; }

  [Field(Length = 4096)]
  public string Text { get; set; }

  public BookReview(Book book, Person reviewer)
    : base(book, reviewer)
  {}
}

Note how Key(1), Key(0) attributes are used to set the position of particular field in multicolumn key.

Sorry, forgot to say that you should indicate that default key generator must not be used for this class, as you set key fields by yourself in constructor:

[KeyGenerator(KeyGeneratorKind.None)]  <!-- Look here
    [HierarchyRoot]
    public class BookReview : Entity
    {
        [Field, Key(1)]
        public Person Reviewer { get; private set; }

        [Field, Key(0)]
        public Book Book { get; private set; }

        [Field(Length = 4096)]
        public string Text { get; set; }

        public BookReview(Book book, Person reviewer)
            : base(book, reviewer)
        { }
    }

Updated at 25.11.2009 9:20:20

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