breeze.js | Breeze for JavaScript clients | REST library

When it comes to deletes, Breeze makes an important distinction between

• (case a) entities that exist only on the client (those in the Added state), and
• (case b) entities that have been persisted on the server.

For an already-persisted entity (case b), Breeze must keep track of that deleted entity, and send the deletion to the server. Any foreign keys on the server must be updated to remove references to the deleted entity, so breeze updates the related client entities accordingly and sends those changes to the server as well.

For a newly-created entity (case a), the server knows nothing about it. When it is "deleted" on the client, Breeze doesn't actually set it Deleted, because it doesn't need to send a deletion to the server. Instead, it sets it Detached.

When an entity is set Detached, its navigation properties are set to null, and it is removed from the EntityManager's cache. Its foreign key properties are not changed, however, so if you detach an entity and re-attach it, the navigation properties will be reconnected. This is true whether the entity was Added or any other state before it became Detached.

More about the entity states can be found in the Breeze documentation