Allow mongodb projection

[rustamwin]

Fixes #3266

[pleerock]

We can't go with such changes. If we keep going with mongodb-specific changes entity-manager/repository is going to be a mess for rdbms and we'll always be blocked on some absolute incompatible features.

I suggest to remove dependency of MongoEntityManager from EntityManager (e.g. remove extends) and completely re-implement MongoEntityManager with mongodb-specific features.

[ElianCordoba]

Seams reasonable, could you provide some initial code/steps to get to that? I don't feel confident enough to take that task ¯_(ツ)_/¯

[pleerock]

1. remove extends EntityManager
2. implement same functions we have before in EntityManager
3. start improving mongodb support

[jyang0110]

why am I getting redirected to here when no solution is given...
Thanks for the work tho

[phil294]

@rustamwin I am trying to understand your pull request: Why is it necessary to add a new projection option? There is already a
https://github.com/typeorm/typeorm/blob/master/src/entity-manager/MongoEntityManager.ts#L96
method which changes select into projection.
Wouldnt the linked issue (#3266) be fixed by simply adjusting convertFindOptionsSelectToProjectCriteria so that nested keys in select are put into the projection too?

since sth like XY.find({ where: { ...conditions }, select: [ ...fields ] }) already works perfectly.

Thanks!

[rustamwin]

Why is it necessary to add a new projection option? There is already a
https://github.com/typeorm/typeorm/blob/master/src/entity-manager/MongoEntityManager.ts#L96
method which changes select into projection.

because select doesn't allow to use mongo projection, but just allow fields
mongodb has a magical projection 😄
https://docs.mongodb.com/manual/reference/operator/projection/

[phil294]

@rustamwin I'm afraid I dont understand. I know that for "select" syntax in MongoDB, you have to use projection. But thats what https://github.com/typeorm/typeorm/blob/master/src/entity-manager/MongoEntityManager.ts#L96 already does, doesnt it? It transforms select into projection when using the mongo driver. convertFindOptionsSelectToProjectCriteria already transforms a ["name", "address.pincode"] into a { name: 1, 'address.pincode': 1 } projection. So it seems to me the nested mongo "select" (internally handled as a projection) should already work. What am I missing?

[gruckion]

Is this going to be merged? Would be nice to have this support.

[kateile]

waiting for this merge. projection is awesome feature in mongoDb

[robbyemmert]

Is this going to be merged? I think this will help my situation (and probably a lot of others, by the look of it).

[rustamwin]

Won't be merged before this:

I suggest to remove dependency of MongoEntityManager from EntityManager (e.g. remove extends) and completely re-implement MongoEntityManager with mongodb-specific features.

[phil294]

Wow since a year and this is still , open. i think i did a bad decision using this ORM. this feature is basic.

@oussaki TypeORM is an Open Source project. Feel free to contribute to this pull request yourself. Otherwise I doubt demanding features from volunteers as if they owe you something will be helpful to anyone.

I found this etiquette guide to make sense in most situations

[imnotjames]

@phil294 I agree with you - one, on your most recent comment about courtesy and etiquette.

Thank you.

But secondly, on reusing select. Reusing select would bypass a lot of the work pleerock had suggested and would maintain a smaller, more cohesive API. We wouldn't have lots of custom mongodb options.

I'd personally prefer that we had a not as great mongodb experience for a more consistent experience across all of these data stores.

If you're after something with super deep mongodb feature support a generic ORM probably ain't gonna cut it. It'll never have feature parity with something that's built out with mongodb as it's primary goal. It can't.

---

I also see that more or less development on this PR has stalled for a few years. I'm gonna close it out because otherwise we end up with folks spamming it with.. well, various comments that aren't constructive towards the PR itself.

Please feel free to open a new PR and definitely continue discussion of this feature request in #3266