BreezeJs Local query returns with entity and empty entity

Question

I'm closely following John Papa's pluralsight course on Angular and Breeze. I also use Entity Framework 6.

At load time, I call a Prime function that clears the cache:

function clearCache() {
    var cachedParents = manager.getEntities('Parent'); // all invoices in cache
    cachedParents.forEach(function (parent) { manager.detachEntity(parent); });
    zStorage.clear();
    manager.clear();
}

and then, loads the info:

return EntityQuery.from('Parents')
    .where('applicationUser.email', '==', userId)
    .expand('Address, Children')
    .toType(entityParent)
    .using(self.manager)
    .execute()
    .then(querySucceeded, self._queryFailed);

that calls the controller with

[HttpGet]
public IQueryable<Parent> Parents()
{
     return _repository.Parents;
}

That returns one record...

Later, on the loading of the view, in the same repository, I request the parent entity from the local cache as follows:

var cachedParents = EntityQuery.from('Parent')
    .toType(entityParent)
    .using(self.manager)
    .executeLocally();

THIS ONE BRINGS TWO ENTITIES, the correct one with Id, name, addres, etc. but also brings an empty entity with Id 0.

I've checked and even if I call the local query right after the remote query, it still brings the correct record AND the empty record.

I also reviewed the response and the json object comes correctly formatted and with only one record.

I've tried clearing the zstorage, the entity manager, detachment of the object, but nothing seems to explain or clear the empty entity.

This behavior only happens in the Parent entity type. No other type shows anything wrong.

Thanks in advance.

DenisK DenisK · Accepted Answer · 2014-07-07T18:52:13

One way to debug this is to subscribe to the entityManager.hasChangesChanged event.

This event will be fired when the "ghost" entity is added. This way, you can trace the call stack by putting a breakpoint inside the event.

So first, ensure that after the clearCache call, the entityManager is empty. (Side note: the call to individually detach the parent entity via manager.detachEntity is actually redundant since you're already calling the manager.clear method at the end)

Then, put a breakpoint inside the hasChangesChanged event as you debug.

Hope this helps.

BreezeJs Local query returns with entity and empty entity

2 Answers