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Show HN: Realm (YC S11), a mobile database

realm.io

21–30 of 105 posts

Re: Show HN: Realm (YC S11), a mobile database

#22
post #15

How do you backup this database? Does it integrate with iCloud or whatever is available on the device?

The database is stored in a single file that is easily backed up. It does not have any explicit integration with iCloud, but you can easily use it to back up a copy of the db, or you can stream the copy back home yourself via ftp or http.

Re: Show HN: Realm (YC S11), a mobile database

#23

Looks interesting! The Swift examples on the homepage seem to be showing Obj-C code: http://cl.ly/image/2r250h3a0A1y

Sorry about that. We’ve been seeing some issues with our CloudFront caches all morning, but if you give it a hard reload or two in your browser, you should eventually see our Swift samples — we’ll keep working to fix the issue.

Re: Show HN: Realm (YC S11), a mobile database

#24
post #13

What does this provide that CoreData doesn't? Whatever it is, it needs to be clearly explained on the landing page. Otherwise it's difficult to understand what problem this solves compared to CoreData.

The big thing is really ease of use. Our blog post has a few more details on that point [0] but basically what we heard over and over and saw ourselves, is that Core Data quickly gets in your way if your app grows [1][2][3]. In essence, we tried with this initial release to offer a rich feature set with a simple API, less side-effects (especially for multi-threaded apps), and a performance that’s even better than usi…

Core Data has been improved and stabilized by Apple for over a decade, is used internally by many first party apps in iOS, is well documented and fully integrated into Xcode, and heavily "marketed" by Apple at WWDC. Any perceived performance issues can be eliminated or reduced by using faults, indexes and improving queries through NSPredicates. Even one of the blog posts you quote above [3] states that if he was starting a new app today, he'd go with Core Data. So I'm just not seeing a need for yet another ORM solution. I'm not saying you shouldn't continue building it, but you guys need to do a better job explaining the differentiation against Core Data. One area could be sync, where Core Data still needs work, and is limited to iCloud's backend. Perhaps that could be your differentiator? But you're not talking about sync yet. So there's work to do in crafting your message. Fwiw, I'm a senior iOS developer who evaluates these things for a living.

Re: Show HN: Realm (YC S11), a mobile database

#25
The foursquare map video shows how the experience with realm is better (and does that well), but it didn't give me any sense of how it's achieving those results. As a developer, I'd love to see an accompanying explanation with details on how the original version works, and how the realm version works.

Re: Show HN: Realm (YC S11), a mobile database

#26
post #24

Earlier quoted context omitted.

The big thing is really ease of use. Our blog post has a few more details on that point [0] but basically what we heard over and over and saw ourselves, is that Core Data quickly gets in your way if your app grows [1][2][3]. In essence, we tried with this initial release to offer a rich feature set with a simple API, less side-effects (especially for multi-threaded apps), and a performance that’s even better than usi…

Core Data has been improved and stabilized by Apple for over a decade, is used internally by many first party apps in iOS, is well documented and fully integrated into Xcode, and heavily "marketed" by Apple at WWDC. Any perceived performance issues can be eliminated or reduced by using faults, indexes and improving queries through NSPredicates. Even one of the blog posts you quote above [3] states that if he was star…

Just to be clear on the topic, since this is an easily misunderstood aspect of Realm: we are not an ORM. We’re not built on SQLite, we’re not mapping to a relational layer, nor are we serializing objects from a third-party data representation: your objects in the language are exactly the same data that’s stored on disk.

We heard a lot of dissatisfaction from the community as far as Core Data is concerned (including from Apple engineers themselves). I’m also not entirely sure you could ever get Core Data performance to the levels we enjoy, since Core Data cannot be any faster than the SQLite underneath, after all. I do want to say that your feedback on how we present ourselves and the work ahead of us is spot on and much appreciated. Many thanks for speaking up, we will work hard to heed your comments & improve.

Re: Show HN: Realm (YC S11), a mobile database

#28
post #24

Earlier quoted context omitted.

Core Data has been improved and stabilized by Apple for over a decade, is used internally by many first party apps in iOS, is well documented and fully integrated into Xcode, and heavily "marketed" by Apple at WWDC. Any perceived performance issues can be eliminated or reduced by using faults, indexes and improving queries through NSPredicates. Even one of the blog posts you quote above [3] states that if he was star…

Just to be clear on the topic, since this is an easily misunderstood aspect of Realm: we are not an ORM. We’re not built on SQLite, we’re not mapping to a relational layer, nor are we serializing objects from a third-party data representation: your objects in the language are exactly the same data that’s stored on disk. We heard a lot of dissatisfaction from the community as far as Core Data is concerned (including f…

Great attitude, and thanks for the clarification. Best of luck!

Re: Show HN: Realm (YC S11), a mobile database

#29
post #25

The foursquare map video shows how the experience with realm is better (and does that well), but it didn't give me any sense of how it's achieving those results. As a developer, I'd love to see an accompanying explanation with details on how the original version works, and how the realm version works.

Absolutely. We didn’t get a chance to clean up the codebase for this app before the launch (it’s actually using an old version of our API that would be confusingly different than what our docs detail) but we’ll try to set up a blogpost about that since I may not be able to do the topic justice in a comment here :)

The short version is that most apps tend to do a query on click, fetch from an API and then cache the results in memory. The Realm version fetches from the API asynchronously in the back, pre-fetching results and writing them form the DB on one thread and reading & displaying them on the map from another. This has a few benefits (& drawbacks). On one hand, you do hit your servers a bit more often at first, and you may actually get so much data in the map that the UI component will start to lag. On the plus side, your data points are cached so you can do a lot less API queries over time (especially for something like Foursquare where users tend to stay in the same area and the dataset of venues doesn’t change that often). You also get better control as a designer or developer, and you can trim down & display relevant datasets on the fly.

To sum up, I’d say the key difference is the availability of a local, concurrent data structure that can easily be updated & read from multiple places (i.e. in a few lines of code if you look at the samples on http://realm.io)

Re: Show HN: Realm (YC S11), a mobile database

#30
post #24

Earlier quoted context omitted.

Core Data has been improved and stabilized by Apple for over a decade, is used internally by many first party apps in iOS, is well documented and fully integrated into Xcode, and heavily "marketed" by Apple at WWDC. Any perceived performance issues can be eliminated or reduced by using faults, indexes and improving queries through NSPredicates. Even one of the blog posts you quote above [3] states that if he was star…

Just to be clear on the topic, since this is an easily misunderstood aspect of Realm: we are not an ORM. We’re not built on SQLite, we’re not mapping to a relational layer, nor are we serializing objects from a third-party data representation: your objects in the language are exactly the same data that’s stored on disk. We heard a lot of dissatisfaction from the community as far as Core Data is concerned (including f…

Just as another data point, I agree with magsafe. I've used Core Data a bit recently and haven't really had any problems with it (though I agree it could be nicer).

My huge, huge, huge problem, on the other hand, is sync. I don't want to get locked into iCloud and the idea of Apple offering multi-platform support is unrealistic.

If you offered this as a cross-platform solution + syncing I'd sign up immediately (it sounds like this might be where you're headed anyway).

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