They act as an application server that allows for all of the notifications when your data flows through their layer in and our of the underlying MongoDB.
Ah, I see. So they are essentially doing this extra step for you, of both persisting and emitting a signal. I suppose this could be done quite simply via an abstraction/wrapper of any database with which you handle all communication to your database. On 21 October 2014 10:26, Marcus Ottosson <[email protected]> wrote: > This layer allows you to emit your signals to connected clients. > > Yeah, it was this I was trying to illustrate with the above update_field() > function; that a user-event is sent to both the view, rendering the field, > *and* the database, persisting the change; whereas in Firebase and > QModel, views can instead be connected directly to the *data-source* > (switching the name from “model” here as you said database and model aren’t > necessarily exchangeable). > > It comes down to the decision of whether you want to host your own > services, or run them in the cloud > > Do you know of a local equivalent of this? The concept of Firebase seems > applicable outside of cloud-hosting, but maybe there’s something I’m > missing. > > > On 21 October 2014 10:20, Justin Israel <[email protected]> wrote: > >> I didn't realize this, but Firebase is an system on top of MongoDB. They >> act as an application server that allows for all of the notifications when >> your data flows through their layer in and our of the underlying MongoDB. >> So really, this just goes to show that the notification layer can be at >> different levels. Either you are doing it in your own application layer >> between a database and the client code. Or you are using a service like >> Firebase. Or even a combination of notifications from Firebase to keep >> multiple application servers notified, while also pushing your own >> notifications to your clients. >> >> On Tue, Oct 21, 2014 at 10:09 PM, Justin Israel <[email protected]> >> wrote: >> >>> Hey Marcus, >>> >>> The way I see it, there is a bit of a difference between the things you >>> are comparing. Yes, from a general perspective a model is something that >>> stores data, but it doesn't necessarily mean that a database and a >>> QAbstractItemModel are interchangeable concepts in a model/view situation. >>> A database is a persistent (or not) store. Your model would wrap around >>> that. Qt even has an equivalent concept with the QSqlTableModel. It uses >>> abstracts an sql store and models it to provide interface-compatible data >>> to views. >>> >>> Now, on to the part where you talk about signals and notifications of >>> changes. It wouldn't be typical to expect to monitor signals from MongoDB >>> in your view (mongodb doesn't even have native triggers). More >>> realistically, you have 3 tiers: The database, the application server, and >>> the client. It would be your application server that handles modeling the >>> database and providing the data to the client. When data changes, it goes >>> through the application server first. This layer allows you to emit your >>> signals to connected clients. Some databases do have integrated >>> notification systems (Postgres has it). And I am sure that is for specific >>> db <-> application server situations. >>> >>> Firebase is a bit more than just a database. I would call it more like a >>> full stack framework. It is a NoSql database, along with a scalable >>> platform, and a flexible API. That notification feature is rolled into the >>> package, in addition to the auth stuff. It shares some qualities with other >>> options like Google appengine: >>> >>> - https://cloud.google.com/appengine/docs/python/datastore/ >>> - https://cloud.google.com/appengine/docs/python/channel/ >>> >>> Or amazon >>> >>> - http://aws.amazon.com/dynamodb/details/ >>> - http://aws.amazon.com/sns/ >>> >>> It comes down to the decision of whether you want to host your own >>> services, or run them in the cloud and let someone else handle all the >>> scalability and reliability, and just give you a full featured API. >>> >>> Does your application design include an application server? If so, I >>> would suggest focusing on having your clients talk to one or more >>> application servers. And let the application servers talk to the database. >>> This insulates your clients from changes on the backend, since anything you >>> might want to change regarding the database can remain transparent to the >>> client code, as long as your application server continues to provide a >>> consistent API. >>> >>> -- justin >>> >>> >>> >>> On Tue, Oct 21, 2014 at 9:43 PM, Marcus Ottosson <[email protected] >>> > wrote: >>> >>>> In QAbstractItemModel, whenever the data changes, a signal is emitted >>>> that we can listen to. E.g. when a particular field changes, the QTreeView >>>> or what have you re-draws to reflect this. >>>> >>>> With web-applications, this doesn’t seem to be the case. Using MongoDB >>>> for instance, interacting with the model (database) typically (seems to) >>>> include an additional interaction with an event (however I’m very new to >>>> it). >>>> >>>> # Exampledef update_field(content): >>>> field.setText(content) # Update visually >>>> database.insert({"key": value}, content) # Update model >>>> >>>> Firebase on the other hand looks more like QAbstractItemModel, in that >>>> for each change there is an event. >>>> >>>> https://www.firebase.com/docs/web/api/query/on.html >>>> >>>> firebaseRef.on('value', function(dataSnapshot) { >>>> // Model was updated >>>> field.setText(dataSnapShot.val()) >>>> }); >>>> >>>> It may be due to familiarity, but it seems more intuitive to me to >>>> listen for changes on a model, than to double-up on updating both views and >>>> models from a controller when it comes to changes to data. >>>> >>>> Are there other databases that does this, that isn’t cloud-based? Is >>>> this a common practice? Why not? >>>> >>>> Best, >>>> Marcus >>>> >>>> -- >>>> *Marcus Ottosson* >>>> [email protected] >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Python Programming for Autodesk Maya" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/python_inside_maya/CAFRtmOALCSxNB%2B3ZbLLLrk7_%3DjQY2nRQDiqt%3DL7X%3Dz9XBLYZAg%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/python_inside_maya/CAFRtmOALCSxNB%2B3ZbLLLrk7_%3DjQY2nRQDiqt%3DL7X%3Dz9XBLYZAg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "Python Programming for Autodesk Maya" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/python_inside_maya/CAPGFgA1VSk3jjOpSk%2BC7wrgjFFHO_6b-0-ueuxgDS3wjtsFDJw%40mail.gmail.com >> <https://groups.google.com/d/msgid/python_inside_maya/CAPGFgA1VSk3jjOpSk%2BC7wrgjFFHO_6b-0-ueuxgDS3wjtsFDJw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > *Marcus Ottosson* > [email protected] > -- *Marcus Ottosson* [email protected] -- You received this message because you are subscribed to the Google Groups "Python Programming for Autodesk Maya" group. 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