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• Problem with Core Data - EXC_BAD_ACCESS

  - by BarrettJ

  I'm using the following code and I'm getting an EXC_BAD_ACCESS when trying to get the count of objects - anyone have any idea why? Oddly enough, the error only happens if the count should be one or greater, if there are no objects it seems to work fine (it outputs null). NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"TVShow" inManagedObjectContext:[self managedObjectContext]]; [fetchRequest setEntity:entity]; [fetchRequest includesPendingChanges]; //NSPredicate *predicate = [NSPredicate predicateWithFormat:@"ID == %@", showId]; //[fetchRequest setPredicate:predicate]; NSError *error; NSLog(@"Generating Count"); NSUInteger count = [[self managedObjectContext] countForFetchRequest:fetchRequest error:&error]; if(count == NSNotFound) { NSLog(@"error"); } else { NSLog(@"%@", count); // EXC_BAD_ACCESS here } [fetchRequest release];

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• NSPredicate acting strange in NSFetchedResultsController

  - by Scott Langendyk

  I feel as if this should be very simple, but it's behaving strangely. I have 3 entities, with a relationship as such Entity A <-- Entity B <<-- Entity C I have an NSFetchedResults controller and I'm trying to filter the results of Entity A using the following predicate. [NSPredicate predicateWithFormat:@"NONE entityB.entityC == %@", self.entityC]; When I try and run the app, the output shows no results. I can alter the predicate slightly to: [NSPredicate predicateWithFormat:@"ANY entityB.entityC == %@", self.entityC]; And it shows me only the results that I want it to filter out. Why is this happening?

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• iPhone: Speeding up a search that's polling 17,000 Core Data objects

  - by randombits

  I have a class that conforms to UISearchDisplayDelegate and contains a UISearchBar. This view is responsible for allowing the user to poll a store of about 17,000 objects that are currently managed by Core Data. Everytime the user types in a character, I created an instance of a SearchOperation (subclasses NSOperation) that queries Core Data to find results that might match the search. The code in the search controller looks something like: - (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope { // Update the filtered array based on the search text and scope in a secondary thread if ([searchText length] < 3) { [filteredList removeAllObjects]; // First clear the filtered array. [self setFilteredList:NULL]; [self.tableView reloadData]; return; } NSDictionary *searchdict = [NSDictionary dictionaryWithObjectsAndKeys:scope, @"scope", searchText, @"searchText", nil]; [aSearchQueue cancelAllOperations]; SearchOperation *searchOp = [[SearchOperation alloc] initWithDelegate:self dataDict:searchdict]; [aSearchQueue addOperation:searchOp]; } And my search is rather straight forward. SearchOperation is a subclass of NSOperation. I overwrote the main method with the following code: - (void)main { if ([self isCancelled]) { return; } NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"MyEntity" inManagedObjectContext:managedObjectContext]; NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; [fetchRequest setEntity:entity]; NSPredicate *predicate = NULL; predicate = [NSPredicate predicateWithFormat:@"(someattr contains[cd] %@)", searchText]; [fetchRequest setPredicate:predicate]; NSError *error = NULL; NSArray *fetchResults = [managedObjectContext executeFetchRequest:fetchRequest error:&error]; [fetchRequest release]; if (self.delegate != nil) [self.delegate didFinishSearching:fetchResults]; [pool drain]; } This code works, but it has several issues. It's slow. Even though I have the search happening in a separate thread other than the UI thread, querying 17,000 objects is clearly not optimal. If I'm not careful, crashes can happen. I set the max concurrent searches in my NSOperationQueue to 1 to avoid this. What else can I do to make this search faster? I think preloading all 17,000 objects into memory might be risky. There has to be a smarter way to conduct this search to give results back to the user faster.

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• Setting a property value on each of the results in a FetchedResults set

  - by RickiG

  Hi On my Core Data Entity "Book" i have a boolean property, 'wasViewed' (NSNumber numberWithBool) that tells me if the Book was "viewed". I would like to implement a sort of "reset" this property for all my NSManagedObjects "Book". So that I can set them all to NO between sessions. I use an NSPredicate to retrieve all the Books like this: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"wasViewed == %@", [NSNumber numberWithBool:YES]]; // code for setting entity, request etc... NSMutableArray *mutableFetchResults = [[[managedObjectContext executeFetchRequest:request error:&error] mutableCopy] autorelease]; This is working just fine, however, now I need to set up a loop, go through each Book object, something like this: for(Book *b in mutableFetchResults) { [b setWasViewed:NO] } Is there a way to perform an action on each element that fits the predicate instead of retrieving it? So instead of executeFetchRequest on a managedObjectContext it could be executeOperationOnFetchRequestResults or something along those lines. Thanks for any input given:)

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• How do I return the entire set / array using NSPredicate?

  - by Prairiedogg

  I'm building a carArray and want to filter the contents conditionally, using an NSPredicate, like so: NSPredicate *pred; switch (carType) { case FreeCar: pred = [NSPredicate predicateWithFormat:@"premium = NO"]; break; case PremiumCar: pred = [NSPredicate predicateWithFormat:@"premium = YES"]; break; default: pred = [NSPredicate predicateWithFormat:@"SOME PREDICATE THAT RETURNS EVERYTHING"]; break; } self.carArray = [aCarArrayIGotFromSomewhere filteredArrayUsingPredicate:pred]; My question is, what is the correct syntax for the value I've stubbed in as SOME PREDICATE THAT RETURNS EVERYTHING which returns all of the instances in the array / set? PS - I know the answer and will post it immediately, just sharing it for everyone's reference as an earlier search on SO did not yield the result.

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• How do I programmatically translate a LINQ query to readable English text that correctly describes t

  - by eniac

  I am working on a project that uses Albahari's PredicateBuilder library http://www.albahari.com/nutshell/ to create a linq expression dynamically at run time. I would like to find a way to translate this dynamically created linq predicate of type Expression<Func<T, bool>> into a readable english statement at runtime. I'll give a statically created linq statement as an example: from p in Purchases select p where p.Price 100 && p.Description != "Bike". For this linq statement I would want to dynamically generate at runtime an english description along the lines of: "You are searching for purchases where the price is greater than 100 and the description is not bike". Are there any libraries that already exist which accomplish this goal, keep in mind I am using PredicateBuilder to dynamically generate the where predicate. If no solution exists how would you go about building a solution? Thanks!

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• using KVO to filter an NSTableView using NSPredicate (with arrays)

  - by KingRufus

  My UI is not updating when I expect it to. The application displays "projects" using a view similar to iTunes -- a source list on the left lets you filter a list (NSTableView) on the right. My filters update properly when they are examining any simple field (like name, a string), but not for arrays (like tags). I'm removing a tag from one of my objects (from an NSMutableArray field called "tags") and I expect it to disappear from the list because it no longer matches the predicate that is bound to my table's NSArrayController. ProjectBrowser.mm: self.filter = NSPredicate* srcPredicate = [NSPredicate predicateWithFormat:@"%@ IN %K", selectedTag, @"tags"]; Project.mm: [self willChangeValueForKey:@"tags"]; [tags removeAllObjects]; [self didChangeValueForKey:@"tags"]; I've also tried this, but the result is the same: [[self mutableArrayValueForKey:@"tags"] removeAllObjects]; Interface Builder setup: a ProjectBrowser object is the XIB's File Owner an NSArrayController (Project Controller) has its Content Array bound to "File's Owner".projects Project Controller's filter predicate is bound to "File's Owner".filter NSTableView's column is bound to "Project Controller".name

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• to-many Core Data fetch request behaves oddly with a new store

  - by Giao

  I have two entities, Department and Person. Department has a to-many relationship to Person. The Person entity has a hireDate property. I'm using the predicate "count(person) = 0 OR none person.hireDate %@" to find Departments without any Persons in them or Departments that haven't hired anyone since a recent date. When the app first starts up (new user experience) and Departments are inserted and no Person have been inserted, the fetch request with this predicate returns nothing. However, if I create insert a new Person entity and delete it, then save the store, the fetch request will return all the Departments. I've found a work around where, I just insert a new Person and delete it, then save the store, the fetch request as I expected it to work. I've found that inserting a new Person and deleting it without saving will not correct the problem. Is this a bug with Core Data or is this a bug with how I've designed my app?

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• E4X in ActionScript

  - by Brian Genisio

  Hey all, Looking at the E4X implementation in ActionScript, it occurs to me that they had to figure out how to do three things that I am not sure can be done within ActionScript regularly: Properties/Getters prefixed with @: var myAttribute = xmlPerson.@name; Nameless functions for filtering: xmlData.person.(/* predicate */) lambda syntax for predicates: xmlData.person.(@name == "Brian") So here is my question: Are these just one-off capabilities (much like Vector.<>) they put in just for E4X, therefore keeping out of reach for us? Or do we, as ActionScript developers, have access to these features? More specifically, I'd love to get access to the expression tree of that lambda predicate for my own code (not tied to the XML classes in any way). I figured out that this is called the "filter operator"... but I am not sure how to harness it. Not sure I can... since ActionScript does not allow for operator overloading :(

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• Self-relation messes up contents in fetching

  - by holographix

  Hi folks, I'm dealing with an annoying problem in core data I've got a table named Character, which is made as follows I'm filling the table in various steps: 1) fill the attributes of the table 2) fill the Character Relation (charRel) FYI charRel is defined as follows I'm feeding the contents by pulling the data from an xml, the feeding code is this curStr = [[NSMutableString stringWithString:[curStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]] retain]; NSLog(@"Parsing relation within these keys %@, in order to get'em associated",curStr); NSArray *chunks = [curStr componentsSeparatedByString: @","]; for( NSString *relId in chunks ) { NSLog(@"Associating %@ with id %@",[currentCharacter valueForKey:@"character_id"], relId); NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"character_id == %@", relId]; [request setEntity:[NSEntityDescription entityForName:@"Character" inManagedObjectContext:[self managedObjectContext] ]]; [request setPredicate:predicate]; NSerror *error = nil; NSArray *results = [[self managedObjectContext] executeFetchRequest:request error:&error]; // error handling code if(error != nil) { NSLog(@"[SYMBOL CORRELATION]: retrieving correlated symbol error: %@", [error localizedDescription]); } else if([results count] > 0) { Character *relatedChar = [results objectAtIndex:0]; // grab the first result in the stack, could be done better! [currentCharacter addCharRelObject:relatedChar]; //VICE VERSA RELATIONS NSArray *charRels = [relatedChar valueForKey:@"charRel"]; BOOL alreadyRelated = NO; for(Character *charRel in charRels) { if([[charRel valueForKey:@"character_id"] isEqual:[currentCharacter valueForKey:@"character_id"]]) { alreadyRelated = YES; break; } } if(!alreadyRelated) { NSLog(@"\n\t\trelating %@ with %@", [relatedChar valueForKey:@"character_id"], [currentCharacter valueForKey:@"character_id"]); [relatedChar addCharRelObject:currentCharacter]; } } else { NSLog(@"[SYMBOL CORRELATION]: related symbol was not found! ##SKIPPING-->"); } [request release]; } NSLog(@"\t\t### TOTAL OF REALTIONS FOR ID %@: %d\n%@", [currentCharacter valueForKey:@"character_id"], [[currentCharacter valueForKey:@"charRel"] count], currentCharacter); error = nil; /* SAVE THE CONTEXT */ if (![managedObjectContext save:&error]) { NSLog(@"Whoops, couldn't save the symbol record: %@", [error localizedDescription]); NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey]; if(detailedErrors != nil && [detailedErrors count] > 0) { for(NSError* detailedError in detailedErrors) { NSLog(@"\n################\t\tDetailedError: %@\n################", [detailedError userInfo]); } } else { NSLog(@" %@", [error userInfo]); } } at this point when I print out the values of the currentCharacter, everything looks perfect. every relation is in its place. in example in this log we can clearly see that this element has got 3 items in charRel: <Character: 0x5593af0> (entity: Character; id: 0x55938c0 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p86> ; data: { catRel = "<relationship fault: 0x9a29db0 'catRel'>"; charRel = ( "0x9a1f870 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p74>", "0x9a14bd0 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p109>", "0x558ba00 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p5>" ); "character_id" = 254; examplesRel = "<relationship fault: 0x9a29df0 'examplesRel'>"; meaning = "\n Left"; pinyin = "\n zu\U01d2"; "pronunciation_it" = "\n zu\U01d2"; strokenumber = 5; text = "\n \n <p>The most ancient form of this symbol"; unicodevalue = "\n \U5de6"; }) then when I'm in need of retrieving this item I perform an extraction, like this: // at first I get the single Character record NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSError *error; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"character_id == %@", self.char_id ]; [request setEntity:[NSEntityDescription entityForName:@"Character" inManagedObjectContext:_context ]]; [request setPredicate:predicate]; NSArray *fetchedObjs = [_context executeFetchRequest:request error:&error]; when, for instance, I print out in NSLog the contents of charRel NSArray *correlations = [singleCharacter valueForKey:@"charRel"]; NSLog(@"CHARACTER OBJECT \n%@", correlations); I get this Relationship fault for (<NSRelationshipDescription: 0x5568520>), name charRel, isOptional 1, isTransient 0, entity Character, renamingIdentifier charRel, validation predicates (), warnings (), versionHashModifier (null), destination entity Character, inverseRelationship (null), minCount 1, maxCount 99 on 0x6937f00 hope that I made myself clear. this thing is driving me insane, I've googled all over world, but I couldn't find a solution (and this make me think to as issue related to bad coding somehow :P). thank you in advance guys. k

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• Building a NSPredicate for a filter

  - by John

  Hi, Just wondering what the best way to build a NSPredicate is if some filters are optional? This is basically for a filter, so if some options aren't selected I don't to filter by them eg. If I have option1 and option2 set for the filter. NSPredicate* predicate = [NSPredicate predicateWithFormat:@"option1 = %@ AND option2 = %@] .... otherwise if just option1 NSPredicate* predicate = [NSPredicate predicateWithFormat:@"option1 = %@] .... The key being there are 10 different options to filter, so I don't want to have to code for the 10x10 possible combinations. Thanks

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• using KVO to update an NSTableView filtered by an NSPredicate

  - by KingRufus

  My UI is not updating when I expect it to. The application displays "projects" using a view similar to iTunes -- a source list on the left lets you filter a list (NSTableView) on the right. My filters update properly when they are examining any simple field (like name, a string), but not for arrays (like tags). I'm removing a tag from one of my objects (from an NSMutableArray field called "tags") and I expect it to disappear from the list because it no longer matches the predicate that is bound to my table's NSArrayController. ProjectBrowser.mm: self.filter = NSPredicate* srcPredicate = [NSPredicate predicateWithFormat:@"%@ IN %K", selectedTag, @"tags"]; Project.mm: [self willChangeValueForKey:@"tags"]; [tags removeAllObjects]; [self didChangeValueForKey:@"tags"]; I've also tried this, but the result is the same: [[self mutableArrayValueForKey:@"tags"] removeAllObjects]; Interface Builder setup: a ProjectBrowser object is the XIB's File Owner an NSArrayController (Project Controller) has its Content Array bound to "File's Owner".projects Project Controller's filter predicate is bound to "File's Owner".filter NSTableView's column is bound to "Project Controller".name

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• Using NSPredicate to filter on both Core attribute and entity

  - by Ben Thompson

  I have two entities in core data (call them entityOne and entityTwo). I have a entityOne<---entityTwo relationship between them. I am now trying to code an NSPredicate to fetch entityTwo objects on the following basis: Fetch entityTwo objects that have a relationship with a specified entityOne object. Filter out those entityTwo objects which have no value for one of their attributes. I am best doing both of these in an NSPredicate or is there a better way? I am trying the following: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(attribute <> "") AND (relationship == entityOne"]; [request setPredicate:predicate]; Any pointers on coding great fully received.

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• Javascript - cannot make static reference to non-static function ....

  - by Ankur

  I am making a reference to the Javascript function splice() on an array and I get the error: "Cannot make a static reference to the non-static function splice()" What's going on - how is this a static reference, aren't I referencing an instance of an Array class and its method - how is that static? $(document).ready( function() { var queryPreds = new Array(); var queryObjs = new Array(); function remFromQuery(predicate) { for(var i=0; i<arrayName.length;i++ ) { if(queryPreds[i]==predicate) queryPreds.splice(i,1); queryObjs.splice(i,1); } } }

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• Partially Modifying an XML serialized document.

  - by Stacey

  I have an XML document, several actually, that will be editable via a front-end UI. I've discovered a problem with this approach (other than the fact that it is using xml files instead of a database... but I cannot change that right now). If one user makes a change while another user is in the process of making a change, then the second one's changes will overwrite the first. I need to be able to request objects from the xml files, change them, and then submit the changes back to the xml file without re-writing the entire file. I've got my entire xml access class posted here (which was formed thanks to wonderful help from stackoverflow!) using System; using System.Linq; using System.Collections; using System.Collections.Generic; namespace Repositories { /// <summary> /// A file base repository represents a data backing that is stored in an .xml file. /// </summary> public partial class Repository<T> : IRepository { /// <summary> /// Default constructor for a file repository /// </summary> public Repository() { } /// <summary> /// Initialize a basic repository with a filename. This will have to be passed from a context to be mapped. /// </summary> /// <param name="filename"></param> public Repository(string filename) { FileName = filename; } /// <summary> /// Discovers a single item from this repository. /// </summary> /// <typeparam name="TItem">The type of item to recover.</typeparam> /// <typeparam name="TCollection">The collection the item belongs to.</typeparam> /// <param name="expression"></param> /// <returns></returns> public TItem Single<TItem, TCollection>(Predicate<TItem> expression) where TCollection : IDisposable, IEnumerable<TItem> { using (var list = List<TCollection>()) { return list.Single(i => expression(i)); } } /// <summary> /// Discovers a collection from the repository, /// </summary> /// <typeparam name="TCollection"></typeparam> /// <returns></returns> public TCollection List<TCollection>() where TCollection : IDisposable { using (var list = System.Xml.Serializer.Deserialize<TCollection>(FileName)) { return (TCollection)list; } } /// <summary> /// Discovers a single item from this repository. /// </summary> /// <typeparam name="TItem">The type of item to recover.</typeparam> /// <typeparam name="TCollection">The collection the item belongs to.</typeparam> /// <param name="expression"></param> /// <returns></returns> public List<TItem> Select<TItem, TCollection>(Predicate<TItem> expression) where TCollection : IDisposable, IEnumerable<TItem> { using (var list = List<TCollection>()) { return list.Where( i => expression(i) ).ToList<TItem>(); } } /// <summary> /// Attempts to save an entire collection. /// </summary> /// <typeparam name="TCollection"></typeparam> /// <param name="collection"></param> /// <returns></returns> public Boolean Save<TCollection>(TCollection collection) { try { // load the collection into an xml reader and try to serialize it. System.Xml.XmlDocument xDoc = new System.Xml.XmlDocument(); xDoc.LoadXml(System.Xml.Serializer.Serialize<TCollection>(collection)); // attempt to flush the file xDoc.Save(FileName); // assume success return true; } catch { return false; } } internal string FileName { get; private set; } } public interface IRepository { TItem Single<TItem, TCollection>(Predicate<TItem> expression) where TCollection : IDisposable, IEnumerable<TItem>; TCollection List<TCollection>() where TCollection : IDisposable; List<TItem> Select<TItem, TCollection>(Predicate<TItem> expression) where TCollection : IDisposable, IEnumerable<TItem>; Boolean Save<TCollection>(TCollection collection); } }

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• mismatchedtoken with antlr syntactic predicates

  - by varzan

  I have the following lexer rules in my grammar file: LINE : 'F' | 'G'; RULE : (('->' ('F' | 'G')) => 'F' | 'G' ) | LINE LINE + | LINE * (ROTATE + LINE+)+ ; fragment ROTATE : ('/' | '\\'); I'm basically trying to match productions that look like F - F/F\F\F/F. It successfully matches stuff like the above, but I'm guessing there's a problem with my syntactic predicate, since G - G produces a MismatchedTokenException. The predicate serves to disambiguate between single letters on the lhs of '-', which I want to be recognized as the LINE token, and those on the rhs, which should be RULEs. Any idea what I'm doing wrong?

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• Is there an Objective-C algorithm like `transform` of the C++ STL?

  - by pesche

  My goal is to have an array that contains all filenames of a specific extension, but without the extension. There's an elegant solution to get all filenames of a specific extension using a predicate filter and instructions on how to split a path into filename and extension, but to combine them I would have to write a loop (not terrible, but not elegant either). Is there a way with Objective-C (may be similar to the predicate mechanism) to apply some function to every element of an array and put the results in a second array, like the transform algorithm of the C++ STL does?

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• NSPredicate aggregate function [SIZE] gives 'unsupported function expression' error

  - by jinglesthula

  iOS 4: I have entities in Core Data (using SQLite, which is a requirement) of: Request Response (which has a property personId) Revision Relationships are: Request <-- Revision Request <-- Response Revision <-- Response (e.g. each request may have many responses; each request/response pair may have many revisions) I'm trying to do a predicate to get all Responses with a given personId that have zero Revisions. Using: (personId == %d) && (Request.Revision[SIZE] == 0) in my predicate string gives me a runtime exception "Unsupported function expression Request.Revision[SIZE]" The documentation seems pretty sparse on aggregate functions, only noting that they exist, but with no syntax or examples. Not sure if it's my syntax or if the SIZE function really isn't supported in iOS.

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• Filtering NSMutableArray based on enum property

  - by Marty

  I've got an NSMutableArray filled with objects of type "GameObject". GameObject has a number of properties, one of which being "gameObjectType" . "gameObjectType" is of type GameObjectTypeEnum. I want to be able to filter this NSMutableArray so only GameObjects of a certain type are returned. I've got the following in place, but it's giving me a "BAD ACCESS" error: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"gameObjectType = %@", gameObjectType]; return [gameObjects filteredArrayUsingPredicate:predicate]; Is it possible to pass a "custom" type (ie, this enum I've defined) into the predicateWithFormat call?

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• JavaScript: filter() for Objects

  - by AgileMeansDoAsLittleAsPossible

  ECMAScript 5 has the filter() prototype for Array types, but not Object types, if I understand correctly. How would I implement a filter() for Objects in JavaScript? Let's say I have this object: var foo = { bar: "Yes" }; And I want to write a filter() that works on Objects: Object.prototype.filter = function(predicate) { var result = {}; for (key in this) { if (this.hasOwnProperty(key) && !predicate(this[key])) { result[key] = this[key]; } } return result; }; This works when I use it in jsfiddle (http://jsfiddle.net/MPUnL/4/), but when I add it to my site that uses jQuery 1.5 and jQuery UI 1.8.9, I get JavaScript errors in FireBug.

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• Is eval the defmacro of javascript?

  - by Florian Margaine

  In Common Lisp, defmacro basically allows us to build our own DSL. I read this page today and it explains something cleverly done: But I wasn't about to write out all these boring predicates myself, so I defined a function that, given a list of words, builds up the text for such a predicate automatically, and then evals it to produce a function. Which just looks like defmacro to me. Is eval the defmacro of javascript? Could it be used as such?

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• Execution plan warnings–The final chapter

  - by Dave Ballantyne

  In my previous posts (here and here), I showed examples of some of the execution plan warnings that have been added to SQL Server 2012.  There is one other warning that is of interest to me : “Unmatched Indexes”. Firstly, how do I know this is the final one ?  The plan is an XML document, right ? So that means that it can have an accompanying XSD.  As an XSD is a schema definition, we can poke around inside it to find interesting things that *could* be in the final XML file. The showplan schema is stored in the folder Microsoft SQL Server\110\Tools\Binn\schemas\sqlserver\2004\07\showplan and by comparing schemas over releases you can get a really good idea of any new functionality that has been added. Here is the section of the Sql Server 2012 showplan schema that has been interesting me so far : <xsd:complexType name="AffectingConvertWarningType"> <xsd:annotation> <xsd:documentation>Warning information for plan-affecting type conversion</xsd:documentation> </xsd:annotation> <xsd:sequence> <!-- Additional information may go here when available --> </xsd:sequence> <xsd:attribute name="ConvertIssue" use="required"> <xsd:simpleType> <xsd:restriction base="xsd:string"> <xsd:enumeration value="Cardinality Estimate" /> <xsd:enumeration value="Seek Plan" /> <!-- to be extended here --> </xsd:restriction> </xsd:simpleType> </xsd:attribute> <xsd:attribute name="Expression" type ="xsd:string" use="required" /></xsd:complexType><xsd:complexType name="WarningsType"> <xsd:annotation> <xsd:documentation>List of all possible iterator or query specific warnings (e.g. hash spilling, no join predicate)</xsd:documentation> </xsd:annotation> <xsd:choice minOccurs="1" maxOccurs="unbounded"> <xsd:element name="ColumnsWithNoStatistics" type="shp:ColumnReferenceListType" minOccurs="0" maxOccurs="1" /> <xsd:element name="SpillToTempDb" type="shp:SpillToTempDbType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="Wait" type="shp:WaitWarningType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="PlanAffectingConvert" type="shp:AffectingConvertWarningType" minOccurs="0" maxOccurs="unbounded" /> </xsd:choice> <xsd:attribute name="NoJoinPredicate" type="xsd:boolean" use="optional" /> <xsd:attribute name="SpatialGuess" type="xsd:boolean" use="optional" /> <xsd:attribute name="UnmatchedIndexes" type="xsd:boolean" use="optional" /> <xsd:attribute name="FullUpdateForOnlineIndexBuild" type="xsd:boolean" use="optional" /></xsd:complexType> I especially like the “to be extended here” comment,  high hopes that we will see more of these in the future.   So “Unmatched Indexes” was a warning that I couldn’t get and many thanks must go to Fabiano Amorim (b|t) for showing me the way.   Filtered indexes were introduced in Sql Server 2008 and are really useful if you only need to index only a portion of the data within a table.  However,  if your SQL code uses a variable as a predicate on the filtered data that matches the filtered condition, then the filtered index cannot be used as, naturally,  the value in the variable may ( and probably will ) change and therefore will need to read data outside the index.  As an aside,  you could use option(recompile) here , in which case the optimizer will build a plan specific to the variable values and use the filtered index,  but that can bring about other problems.   To demonstrate this warning, we need to generate some test data :   DROP TABLE #TestTab1GOCREATE TABLE #TestTab1 (Col1 Int not null, Col2 Char(7500) not null, Quantity Int not null)GOINSERT INTO #TestTab1 VALUES (1,1,1),(1,2,5),(1,2,10),(1,3,20), (2,1,101),(2,2,105),(2,2,110),(2,3,120)GO and then add a filtered index CREATE INDEX ixFilter ON #TestTab1 (Col1)WHERE Quantity = 122 Now if we execute SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = 122 We will see the filtered index being scanned But if we parameterize the query DECLARE @i INT = 122SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = @i The plan is very different a table scan, as the value of the variable used in the predicate can change at run time, and also we see the familiar warning triangle. If we now look at the properties pane, we will see two pieces of information “Warnings” and “UnmatchedIndexes”. So, handily, we are being told which filtered index is not being used due to parameterization.

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• Improving Comparison Operators and Window Functions

  It is dangerous to assume that your data is sound. SQL already has intrinsic ways to cope with missing, or unknown data in its comparison predicate operators, or Theta operators. Can SQL be more effective in the way it deals with data quality? Joe Celko describes how the SQL Standard could soon evolve to deal with data in ways that allow aggregation and windowing in cases where the data quality is less than perfect

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• June 2013 release of SSDT contains a minor bug that you should be aware of

  - by jamiet

  I have discovered what seems, to me, like a bug in the June 2013 release of SSDT and given the problems that it created yesterday on my current gig I thought it prudent to write this blog post to inform people of it. I’ve built a very simple SSDT project to reproduce the problem that has just two tables, [Table1] and [Table2], and also a procedure [Procedure1]: The two tables have exactly the same definition, both a have a single column called [Id] of type integer. CREATE TABLE [dbo].[Table1] (     [Id] INT NOT NULL PRIMARY KEY ) My stored procedure simply joins the two together, orders them by the column used in the join predicate, and returns the results: CREATE PROCEDURE [dbo].[Procedure1] AS     SELECT t1.*     FROM    Table1 t1     INNER JOIN Table2 t2         ON    t1.Id = t2.Id     ORDER BY Id Now if I create those three objects manually and then execute the stored procedure, it works fine: So we know that the code works. Unfortunately, SSDT thinks that there is an error here: The text of that error is: Procedure: [dbo].[Procedure1] contains an unresolved reference to an object. Either the object does not exist or the reference is ambiguous because it could refer to any of the following objects: [dbo].[Table1].[Id] or [dbo].[Table2].[Id]. Its complaining that the [Id] field in the ORDER BY clause is ambiguous. Now you may well be thinking at this point “OK, just stick a table alias into the ORDER BY predicate and everything will be fine!” Well that’s true, but there’s a bigger problem here. One of the developers at my current client installed this drop of SSDT and all of a sudden all the builds started failing on his machine – he had errors left right and centre because, as it transpires, we have a fair bit of code that exhibits this scenario.  Worse, previous installations of SSDT do not flag this code as erroneous and therein lies the rub. We immediately had a mass panic where we had to run around the department to our developers (of which there are many) ensuring that none of them should upgrade their SSDT installation if they wanted to carry on being productive for the rest of the day. Also bear in mind that as soon as a new drop of SSDT comes out then the previous version is instantly unavailable so rolling back is going to be impossible unless you have created an administrative install of SSDT for that previous version. Just thought you should know! In the grand schema of things this isn’t a big deal as the bug can be worked around with a simple code modification but forewarned is forearmed so they say! Last thing to say, if you want to know which version of SSDT you are running check my blog post Which version of SSDT Database Projects do I have installed? @Jamiet

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• Specification

  Generally saying Specification is a predicate that determines if an object does or does not satisfy some criteria. By using Specifications you could easily recombine business logic together using boolean logic.Have you ever thought that bool TryParse(string s, out int result) is pattern?

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