iPhone-核心数据错误 'NSInvalidArgumentException'，原因: 'Unimplemented SQL generation for predicate'

Question

我是 iPhone 开发新手。我正在尝试使用 iphone 核心数据存储一些数据。当我尝试保存时，我收到类似错误。

Detected an attempt to call a symbol in system libraries that is not present on the         
_Unwind_Resume called from function -[NSSQLAdapter    
 _newSelectStatementWithFetchRequest:ignoreInheritance:] in image CoreData.

2012-05-28 12:05:38.179 FYPV1[6460:207] *** Terminating app due to uncaught exception
 'NSInvalidArgumentException', reason: 'Unimplemented SQL generation for predicate 
(surname MATCHES $search_surname)'
*** Call stack at first throw:
(
0   CoreFoundation                      0x02668b99 __exceptionPreprocess + 185
1   libobjc.A.dylib                     0x027b840e objc_exception_throw + 47
2   CoreData                            0x0003be86 -[NSSQLGenerator generateSQLStatementForFetchRequest:ignoreInheritance:countOnly:] + 1254
3   CoreData                            0x0003b6f0 -[NSSQLAdapter _newSelectStatementWithFetchRequest:ignoreInheritance:] + 480
4   CoreData                            0x0003b501 -[NSSQLAdapter newSelectStatementWithFetchRequest:] + 49
5   CoreData                            0x0003b3ae -[NSSQLCore newRowsForFetchPlan:] + 430
6   CoreData                            0x0003ab09 -[NSSQLCore objectsForFetchRequest:inContext:] + 297
7   CoreData                            0x0003a6fe -[NSSQLCore executeRequest:withContext:error:] + 206
8   CoreData                            0x000e891c -[NSPersistentStoreCoordinator executeRequest:withContext:error:] + 1084
9   CoreData                            0x00037897 -[NSManagedObjectContext executeFetchRequest:error:] + 359
10  FYPV1                               0x0000715f -[Contacts saveContacts:] + 367
11  UIKit                               0x001fc7f8 -[UIApplication sendAction:to:from:forEvent:] + 119
12  UIKit                               0x00287de0 -[UIControl sendAction:to:forEvent:] + 67
13  UIKit                               0x0028a262 -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 527
14  UIKit                               0x00288e0f -[UIControl touchesEnded:withEvent:] + 458
15  UIKit                               0x002203d0 -[UIWindow _sendTouchesForEvent:] + 567
16  UIKit                               0x00201cb4 -[UIApplication sendEvent:] + 447
17  UIKit                               0x002069bf _UIApplicationHandleEvent + 7672
18  GraphicsServices                    0x02f48822 PurpleEventCallback + 1550
19  CoreFoundation                      0x02649ff4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
20  CoreFoundation                      0x025aa807 __CFRunLoopDoSource1 + 215
21  CoreFoundation                      0x025a7a93 __CFRunLoopRun + 979
22  CoreFoundation                      0x025a7350 CFRunLoopRunSpecific + 208
23  CoreFoundation                      0x025a7271 CFRunLoopRunInMode + 97
24  GraphicsServices                    0x02f4700c GSEventRunModal + 217
25  GraphicsServices                    0x02f470d1 GSEventRun + 115
26  UIKit                               0x0020aaf2 UIApplicationMain + 1160
27  FYPV1                               0x00001e59 main + 121
28  FYPV1                               0x00001dd5 start + 53
)
terminate called after throwing an instance of 'NSException'

如何解决这个问题。

这是我用于保存数据的代码。

   NSError *error;  

    NSDictionary *subs = [NSDictionary 
                          dictionaryWithObjectsAndKeys:fetchContact.first_name, @"search_firstname",fetchContact.surname,@"search_surname", nil];

    NSFetchRequest *fetchRequestCheckNil = 
    [managedObjectModel fetchRequestFromTemplateWithName:
     @"Fetchaddcontact" substitutionVariables:subs];

    NSArray *fetchedObjects=[context executeFetchRequest:fetchRequestCheckNil error:nil];
    if ([fetchedObjects count]>0) {
        for (ENTITYADDCONTACTS *contactDetails
             in fetchedObjects) {

            [self updateDBModel:contactDetails];
        }
    }
else {   
    ENTITYADDCONTACTS *contactDetails;
    contactDetails = [NSEntityDescription
                      insertNewObjectForEntityForName:@"ENTITYADDCONTACTS" 
                      inManagedObjectContext:context]; 
    [self updateDBModel:contactDetails];
    }

if (![context save:&error]) {
    NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
}

Answer 1

根据Predicate Programming Guide在约束和限制部分，您不能将 MATCHES 关键字与 sqlite 持久存储一起使用。

引用:

The matches operator uses regex, so is not supported by Core Data’s SQL store— although it does work with in-memory filtering.

在你的情况下，我会使用 BEGINSWITH 或 LIKE。请注意，BEGINSWITH 具有性能优势，因此我建议尽可能使用它。

以下是字符串的可用谓词比较:

String comparisons are by default case and diacritic sensitive. You can modify an operator using the key characters c and d within square braces to specify case and diacritic insensitivity respectively, for example firstName BEGINSWITH[cd] $FIRST_NAME.

BEGINSWITH

The left-hand expression begins with the right-hand expression.

CONTAINS

The left-hand expression contains the right-hand expression.

ENDSWITH

The left-hand expression ends with the right-hand expression.

LIKE

The left hand expression equals the right-hand expression: ? and * are allowed as wildcard characters, where ? matches 1 character and * matches 0 or more characters. In Mac OS X v10.4, wildcard characters do not match newline characters.

MATCHES

The left hand expression equals the right hand expression using a regex-style comparison according to ICU v3 (for more details see the ICU User Guide for Regular Expressions).

这里的异常(exception)是 MATCHES，正如我之前所说，它不能与 sqlite 持久存储一起使用。除此之外，您可以使用普通的 == 进行严格的相等比较。