Awesome, thank you. For anyone else who stumbles upon this question looking for something similar, check out Apple's DerivedProperty example:
http://developer.apple.com/library/mac/#samplecode/DerivedProperty/Introduction/Intro.html It has examples on using the <= & > string comparison trick as well as normalizing strings for indexing. On 2011-07-08, at 2:40 PM, The Karl Adam wrote: > Well, when I said ANY, I really meant "IN termsArray", but for the > partial matches that you want your approach is fine, you'll just want > to use > & <= with character evaluations to speed this up. Check the > 2010 CoreData Performance session from WWDC for more details, but it's > a standard SQL trick to speed up string comparisons. > > _Karl > > On Thu, Jul 7, 2011 at 10:38 AM, Indragie Karunaratne > <cocoa...@indragie.com> wrote: >> I came up with this code earlier: >> NSArray *searchTerms = [cleanedQuery componentsSeparatedByString:@" "]; >> NSPredicate *basePredicate = [NSPredicate >> predicateWithFormat:@"SUBQUERY(keywords, $keyword, $keyword.name BEGINSWITH >> $QUERY).@count != 0"]; >> NSMutableArray *subpredicates = [NSMutableArray array]; >> for (NSString *searchTerm in searchTerms) { >> NSDictionary *sub = [NSDictionary >> dictionaryWithObjectsAndKeys:searchTerm, @"QUERY", nil]; >> NSPredicate *termPredicate = [basePredicate >> predicateWithSubstitutionVariables:sub]; >> [subpredicates addObject:termPredicate]; >> } >> NSPredicate *combinedPredicate = [NSCompoundPredicate >> andPredicateWithSubpredicates:subpredicates]; >> >> This doesn't use "ANY" as you mentioned (not sure exactly how I would use >> that) but it works. However, I'm sure there's a better way to simplify this >> instead of using a giant compound AND predicate to match each one of the >> search terms. Is there any way to simplify this? >> Thanks >> On 2011-07-07, at 11:23 AM, The Karl Adam wrote: >> >> You want to be using SUBQUERY() to match ANY keywords. Check the docs >> for the predicate reference details for this. >> >> _Karl >> >> On Wed, Jul 6, 2011 at 8:23 PM, Indragie Karunaratne >> <cocoa...@indragie.com> wrote: >> >> Hi all, >> >> I have a Core Data object model that I'm trying to write a fetch predicate >> for (to use for search). Quick explanation of the model: >> >> We'll call the main entity "Book". There's also a "Keyword" entity. The >> Book entity has a to-many relationship with the Keyword entity called >> "keywords". In turn, the Keyword entity has an inverse relationship with the >> Book entity called "book". The Keyword entity has a single attribute called >> "name". So basically, each Book has Keywords that describe it. >> >> For my search, I have an array of search terms. I need a predicate that I >> can use on fetch requests for the Book entity that will evaluate to TRUE if >> ALL of the search terms have a corresponding Keyword in that the "name" >> property begins with the search term. >> >> For example: >> >> There are three books: >> >> Book1 - keywords: {"fiction", "scifi"} >> >> Book2 - keywords: {"nonfiction"} >> >> If the search terms were {"fic", "nonfic", "sci"} the resulting fetched >> array would contain NOTHING because none of the books have keywords that >> begin with all 3 of those search terms.. >> >> However, if the search terms were {"fic", "sci"}, the resulting fetched >> array would contain Book1 since its keywords "fiction" and "scifi" begin >> with the two search terms "fic" and "sci". The key part here is that ALL of >> the search terms have to have a corresponding keyword as demonstrated above >> for the predicate to evaluate to true. >> >> I hope I've explained this problem well enough, it's hard to put this stuff >> into words ;-) >> >> Any help is appreciated, >> >> Indragie_______________________________________________ >> >> 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: >> >> http://lists.apple.com/mailman/options/cocoa-dev/karl.adam%40gmail.com >> >> This email sent to karl.a...@gmail.com >> >> >> _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
