On Apr 8, 2014, at 5:31 PM, BareFeetWare <list.develo...@barefeetware.com> wrote:
>> One option is to use SQLite. I've been putting together an open source >> "BFWQuery" library to hopefully simplify the whole thing, by letting you >> treat a database query just like an array of dictionaries. It uses FMDB >> (thanks Gus). >> eg: query.resultArray[row][columnName] >> >> Here is an example: >> >> ... to just get row 3's value for Name: >> >> query.resultArray[3][@"Name"]; >> >> That's all there is to it. >> >> Behind the scenes, BFWQuery only retrieves rows from the database as >> requested, so it doesn't create an in memory array containing all of the >> results. On 9 Apr 2014, at 12:38 pm, Jens Alfke <j...@mooseyard.com> wrote: > Watch out: I have found this degree of abstraction to become a major > performance bottleneck. It results in large numbers of object allocations and > message-sends during query evaluation. Very good point. One of my objectives with BFWQuery is avoid extra object allocations. The resultArray object is a subclass of NSArray, to make it simple for the average Cocoa programmer to use. Behind the scenes, it doesn't allocate objects in an array, but fires off the needed SQLite calls when an actual object is requested. > The query API in FMDB itself is more efficient, and I think clearer, although > not perfect. FMDB is great at providing an Objective-C wrapper for SQLite, but you still need to know how to deal with SQLite's results (eg get the next row from a result until exhausted). > In my current usage I make sure to only use the numeric-indexed accessors > (i.e. get column 2 rather than column “Latitude”) because they’re much faster. That's interesting. I'll have to try some performance benchmarks and see if I can make that faster, if needed. In the meantime, BFWQuery also allows you to specify the column by number, which calls the same FMDB method that I think you're using, eg: query.resultArray[3][2]; // row 3, column 2 Thanks, Tom Look for me at WWDC 2014 Tom Brodhurst-Hill BareFeetWare 👣 -- iPhone/iPad/iPod and Mac software development, specialising in databases develo...@barefeetware.com -- Follow us on Twitter: http://twitter.com/barefeetware/ Like us on Facebook: http://www.facebook.com/BareFeetWare _______________________________________________ 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
