Jens Thanks for these notes - extremely helpful. I think I will kick off with Realm and see where I get too.
Peter > On 4 Jun 2016, at 20:36, Jens Alfke <j...@mooseyard.com> wrote: > > >> On Jun 4, 2016, at 9:51 AM, Peter Hudson <peter.hud...@me.com >> <mailto:peter.hud...@me.com>> wrote: >> >> “If your app’s performance is suffering because of large files, then use >> streams instead, and try to only read the part of the file that’s necessary.” >> Could you point me at some material about this technique ? It sounds very >> interesting. > > At a low level, you can use NSStream to read/write files. Or just use the C > standard library (fopen, fread, etc.) > > At a high level, I can’t say that much since I don’t know what your file > format is. If it’s something like an NSArchive, there’s no alternative to > reading the entire file at once. If it’s an XML property list, you could use > NSXMLParser to stream it and pick out just the parts you need, although this > also gets expensive if you have to keep parsing the file over and over to > read different parts. > >> I will check out the database approach as well. I have steered clear of >> using databases as our users are mostly individuals with little or no tech >> support. The idea has always been to keep things simple and maintenance free. > > You’re thinking of a database _server_ like MySQL or MongoDB. Those run as > separate processes and require administration. The databases I mentioned are > embedded: they’re just libraries that you link into your app, which read and > write a data file (or a directory in LevelDB’s case.) To the end user it’s no > different than any other file format. > > Any Core Data app stores its documents this way, using SQLite by default. > There are also zillions more apps that use FMDB (an Objective-C wrapper > around SQLite) or just SQLite directly. Going with that does require that you > learn about relational databases and SQL syntax, though. Another option is > Realm, a very popular mobile database with a nice Obj-C or Swift API. > > (There’s also the project I work on, Couchbase Lite, which fits in this > category. It has some more overhead, though, because it also performs full > multi-master data sync with servers or peers. This is awesome if you want > that feature, but if you’re just getting started with databases it adds to > the learning curve.) > > Thinking through all the DB options, I’d suggest you look at Realm > (http://realm.io <http://realm.io/>). It’s very easy to understand even if > you don’t know databases, and the APIs are easy to use. The drawback is that > it will probably require that you rethink and re-implement your data model > layer based on its persistent object model. > > If you don’t want to refactor that much, see whether there are any good Cocoa > wrappers around LevelDB, LMDB or RocksDB. (I’m skipping over Kyoto Cabinet > because I just remembered it’s GPL-licensed, and you probably want to stay > away from that.) They’ll provide a simple API that looks like an dictionary > that maps strings to binary data. Then you can break your data into small > bits and read and write them independently. > > —Jens _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
