Is it possible to create a record without assigning a PK & saving?

[cha0s]

I'd like to be able to create an instance of a model without actually saving it or generating a PK (ID would equal null). Is this possible? I'd like to get an instance with all defaults populated, etc. but not actually save it.

[kevinburke]

I'd also like to do this; is this possible? if so could you document it?

[particlebanana]

This should work: new Pet._model(values);

[cha0s]

Using an underscored method is a code smell. Can we have this as a public API, please?

[particlebanana]

Sure mind putting together a pull request?

[cha0s]

Yup I'll get to this later tonight

Sent from my T-Mobile 4G LTE Device

-------- Original message --------

From: Cody Stoltman notifications@github.com

Date:01/16/2015 12:17 PM (GMT-06:00)

To: balderdashy/waterline waterline@noreply.github.com

Cc: Ruben Rodriguez cha0s@therealcha0s.net

Subject: Re: [waterline] Is it possible to create a record without assigning a PK & saving? (#763)

Sure mind putting together a pull request?

—
Reply to this email directly or view it on GitHub.

[cha0s]

Do you have a preference about the syntax? In the project I desired this functionality in, I augmented all collections with .instantiate, so I could do var user = User.instantiate();.

Does that seem like a good name? Should we go with instance, or something else do you think?

Might as well talk about it a little before I bother with a PR :)

[andrewjmead]

+1 for this. I wouldn't mind helping out with a PR as waterline has saved me a ton of development and maintenance time.

My use case is creating multiple instances of a model, but only if they are all valid.

[rishabhmhjn]

Was any method to support this feature added?

[devinivy]

No, there wasn't, but I would love to see a PR for this! Using Collection._model({/* record */}) still works (and I expect it will work until there is a new, non-backwards-compatible version of waterline), though it doesn't feel great to use the private method.

[ejlangev]

Collection._model({ /* data */}) doesn't seem to work very well. I'm using waterline 0.10.26. The method initially works and returns an instance of the model but if I try to call save on that model I immediately get an error "Error: No Primary Key set to update the record with! Primary Key must have a value, it can't be an optional value."

Some example code:

var user = User._model({ email: 'foo@bar.com' });

user.save()
  .then(function() {
    console.log(user.id);
  })
  .catch(function(err) {
    console.log(err);
  });

Is there another workaround I can use for now? Otherwise are there any plans to make a method providing this functionality available through a public api? I'd be willing to submit a pull request that implements that if it's wanted. There's an existing package called sails-model-new that seems to do most of what I'm looking for. It's also supported by many other ORMs.

[devinivy]

Ah, correct– save() only really knows how to perform an update. I'm not sure. I never really use it this way. Maybe Collection.create(modelInstance) works for your purposes.

[elennaro]

I have a similar problem:

    /**
     * MongoDB native findAndUpdate
     * @name DbHelperService._findAndUpdate
     * @param {Object} criteria
     * @param {Object} model Waterline model
     * @param {Object} update values to update { key: value }
     * @param {Function} cb
     * @private
     */
    _findAndUpdate: function (criteria, model, update, cb) {
        console.log('0000', model);
        model.native(function (err, collection) {
            if (err)
                return cb(err);

            collection.findOneAndUpdate(criteria, update, { new: true }, function (err, result) {
                cb(err, result && result.value && new model._model(result.value));
            });
        });
    }

this method does not return a good model, for example it does not convert _id<BSONObject> to id<String>.

Help, please!

[devinivy]

sails-mongo has a utility method to normalize results based upon a schema: https://github.com/balderdashy/sails-mongo/blob/master/lib/utils.js#L78-L96

[ejlangev]

Maybe Collection.create(modelInstance) works for your purposes.

Unfortunately it doesn't in this case. I'm trying to build an adapter between waterline and factory girl and part of the interface is the ability to build a record without saving it and then subsequently save it later on. I hacked around it myself for now but would be nice to fix the underlying issue so I can build the adapter into a real node package and release it. I'll try to submit a pull request that fixes this since it seems like you're open to it.

[devinivy]

I am open to it– not sure where @particlebanana and others are with this. But at least in the next big waterline release, I would love to see a proper public API for creating model instances.

[elennaro]

@devinivy +10000547

[particlebanana]

Yeah having .save do a create if there is no primary key is probably an ok solution or just allowing the .create method to accept a model instance would be the easiest. Just check if the data has a toObject method and if so call it.

[ejlangev]

I think I like the former solution of .save doing a create if there is no primary key. What would the create method do if it accepts a model instance that already has a primary key? Would it create a new record or try to update the existing one. Seems like an easy mistake to make.