Exists<t> method to Objectmanager

BIZ BIZ Feature Requests
1

Having exists method in object manager might help developer a little bit.
Sometimes it's enough to check that record with key exists, not the content.
Instead of writing

  lpos := om.Find<Tpointofsale>(aPosId);
  if not assigned(lpos) then
    raise EXDataHttpException.Create(404,'Point of sale not found');

on could write

  if not om.exists<tPointOfSale>(aPosid) then
      raise EXDataHttpException.Create(404,'Point of sale not found');

benefit of this is that later version could produce sql like select 1 from pointofsale where id='00001' instead of
select all fields from pointofsale where ...
with small number of fields that isn't an issue but if you have many fields where is some performance loss.

2

But you can use projections to speed up:

if om.Find<Tpointofsale>.Select(Linq['Id']).Where(Linq.IdEq(aPosId)) = nil then
  raise EXDataHttpException.Create(404,'Point of sale not found');

And then, of course, you can wrap it in a function, or even a helper class for TObjectManager.

3

I know that, but there is small downside of it.
If i write exists method using that helper like that, there is huge risks some one uses it and later during same manager life time tries to access properties of same entity - which aren't loaded.

4

You can then use a different manager. Just create a manager, execute the method, and destroy it. Creating the manager is very lightweight.

5

Ah, of course, that makes sense.

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