iOS CoreData NSPredicate一次查询多个属性

Question

我试图用一个UISearchBar查询的多个属性NSManagedObject 我有一个NSManagedObject叫Person,每个人都有一个name和socialSecurity财产.现在我的代码可以为其中一个属性或另一个属性执行搜索(获取),但不能同时执行这两个属性.

- (void) performFetch
{       
    [NSFetchedResultsController deleteCacheWithName:@"Master"];  

    // Init a fetch request
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"MainObject" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];

    // Apply an ascending sort for the color items
    //NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"Term" ascending:YES selector:nil];
    NSSortDescriptor *sortDescriptor;
    sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"fullName" ascending:YES selector:@selector(caseInsensitiveCompare:)];    

    NSArray *descriptors = [NSArray arrayWithObject:sortDescriptor];
    [fetchRequest setSortDescriptors:descriptors];

    // Recover query
    NSString *query = self.searchDisplayController.searchBar.text;
    //if (query && query.length) fetchRequest.predicate = [NSPredicate predicateWithFormat:@"Term contains[cd] %@", query];
    if(searchValue==1)
    {
        if (query && query.length) fetchRequest.predicate = [NSPredicate predicateWithFormat:@"name contains[cd] %@", query];
    }
    else {
        if (query && query.length) fetchRequest.predicate = [NSPredicate predicateWithFormat:@"socialSecurity contains[cd] %@", query];
    }        

    // Init the fetched results controller
    NSError *error;
    self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"pLLetter" cacheName:nil];

    self.fetchedResultsController.delegate = self;

    if (![[self fetchedResultsController] performFetch:&error]) NSLog(@"Error: %@", [error localizedDescription]);

    [self.tableView reloadData];
}

我不知道如何把这两个属性放到这个陈述中......

if (query && query.length) fetchRequest.predicate = [NSPredicate predicateWithFormat:@"name contains[cd] %@", query];

任何帮助或想法将不胜感激.

Answer 1

你可以用一个NSCompoundPredicate.

像这样:

NSPredicate *predicateName = [NSPredicate predicateWithFormat:@"name contains[cd] %@", query];
NSPredicate *predicateSSID = [NSPredicate predicateWithFormat:@"socialSecurity contains[cd] %@", query];
NSArray *subPredicates = [NSArray arrayWithObjects:predicateName, predicateSSID, nil];

NSPredicate *orPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:subPredicates];

request.predicate = orPredicate;

有一NSCompoundPredicate对AND过:andPredicateWithSubpredicates:

Answer 2

您可以NSPredicate使用常用的布尔操作数(如AND/OR)在多个搜索项中附加.

这样的事情应该可以解决问题.

[NSPredicate predicateWithFormat:@"name contains[cd] %@ OR ssid contains[cd] %@", query, query];

希望有帮助:)

Answer 3

除了@Matthias的答案,您还可以使用NSCompoundPredicate进行这样的AND操作.

Obj-C - AND

NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"X == 1"];
NSPredicate *predicate2 = [NSPredicate predicateWithFormat:@"X == 2"];
NSPredicate *predicate = [NSCompoundPredicate andPredicateWithSubpredicates:@[predicate1, predicate2]];

斯威夫特 - 和

let predicate1:NSPredicate = NSPredicate(format: "X == 1")
let predicate2:NSPredicate = NSPredicate(format: "Y == 2")
let predicate:NSPredicate  = NSCompoundPredicate(andPredicateWithSubpredicates: [predicate1,predicate2] )

斯威夫特3 - 和

    let predicate1 = NSPredicate(format: "X == 1")
    let predicate2 = NSPredicate(format: "Y == 2")
    let predicateCompound = NSCompoundPredicate(type: .and, subpredicates: [predicate1,predicate2])

Answer 4

Swift2的完整解决方案

let request = NSFetchRequest(entityName: "Location")
let subPredicate1 = NSPredicate(format: "(name = %@)", searchString)
let subPredicate2 = NSPredicate(format: "(street = %@)", searchString)
let subPredicate3 = NSPredicate(format: "(city = %@)", searchString)

request.predicate = NSCompoundPredicate(type: .OrPredicateType, subpredicates: [subPredicate1, subPredicate2, subPredicate3])