How are Value Objects stored in the database?

by

It’s ok to store Value Objects in a separate table, for the very reasons you’ve described. However, I think you’re misunderstanding Entities vs VOs – it’s not a persistence related concern.

Here’s an example:

Assume that a Company and Person both have the same mail Address. Which of these statements do consider valid?

  1. “If I modify Company.Address, I want
    Person.Address to automatically get
    those changes”
  2. “If I modify Company.Address, it
    must not affect Person.Address”

If 1 is true, Address should be an Entity, and therefore has it’s own table

If 2 is true, Address should be a Value Object. It could be stored as a component within the parent Entity’s table, or it could have it’s own table (better database normalisation).

As you can see, how Address is persisted has nothing to do with Entity/VO semantics.

More Related Contents:

  1. Value vs Entity objects (Domain Driven Design)
  2. What are the benefits of Persistence Ignorance?
  3. Is it ok for entities to access repositories?
  4. Where do I find some good examples for DDD? [closed]
  5. Communicating between two Bounded Contexts in DDD
  6. Aggregate Root references other aggregate roots
  7. EF codefirst : Should I initialize navigation properties?
  8. Making Entity Class Closed for Changes
  9. Who should handle the conditions in complex queries, the data mapper or the service layer?
  10. Domain Driven Design: Domain Service, Application Service [closed]
  11. What is the difference between DAO and Repository patterns?
  12. Should services always return DTOs, or can they also return domain models?
  13. Persist Data by Programming Against Interface
  14. Should I abstract the validation framework from Domain layer?
  15. How to remove unit of work functionality from repositories using IOC
  16. Refactoring code to avoid anti-pattern
  17. DDD – the rule that Entities can’t access Repositories directly
  18. The repository itself is not usually tested?
  19. MVVM: Binding to Model while keeping Model in sync with a server version
  20. Multiple Aggregates / Repositories in one Transaction
  21. ASP.MVC: Repository that reflects IQueryable but not Linq to SQL, DDD How To question
  22. Get all associate/composite objects inside an object (in Abstract way)
  23. How to pass Current User Information to all Layers in DDD
  24. IQueryable & Repositories – take 2?
  25. DDD Approach to Access External Information
  26. POCO’s, behavior and Peristance Igorance
  27. Polymorphism: Is ORM entity a Domain Entity or Data Entity?
  28. How to handle set based consistency validation in CQRS?
  29. DDD, Anti Corruption layer, how-to?
  30. Why does the entity framework need an ICollection for lazy loading?

Leave a Comment