Predicate search not working (core data) - objective-c

Question

When inserting in the "FilterProperty" entity, I use the following code in a category "FilterProperty+Manage.h"
+(FilterProperty *)insertFilterPropertyWithName:(NSString *)filterPropertyName forManagedObjectContext:(NSManagedObjectContext *)managedObjectContext forFriendlyName:(NSString *)friendlyName
forDefaultValue:(NSNumber *)defaultValue forMinValue:(NSNumber *)minValue forMaxValue:(NSNumber *)maxValue forType:(NSNumber *)type forBelongsToFilter:(Filter *)filter
{
FilterProperty *fp = nil;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"FilterProperty" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"name = %# AND belongsToFilter.name = %#", filterPropertyName, filter.name];
[fetchRequest setPredicate:predicate];
NSError *error = nil;
NSArray *fetchedObjects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
if (fetchedObjects == nil)
{
return nil;
}
if (fetchedObjects != nil && fetchedObjects.count > 0)
{
fp = fetchedObjects.firstObject;
}
else if(fetchedObjects != nil && fetchedObjects.count == 0)
{
fp = [NSEntityDescription insertNewObjectForEntityForName:#"FilterProperty" inManagedObjectContext:managedObjectContext];
fp.name = filterPropertyName;
fp.friendlyName = friendlyName;
fp.defaultValue = defaultValue;
fp.minValue = minValue;
fp.maxValue = maxValue;
fp.belongsToFilter = filter;
fp.type = type;
}
return fp;
}
No while searching, I do the following:
+(NSArray *)getAllFilterPropertiesForFilter:(Filter *)filter forManagedObjectContext (NSManagedObjectContext *)managedObjectContext
{
NSArray *set = nil;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"FilterProperty" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"belongsToFilter.name = %#", filter.name];
[fetchRequest setPredicate:predicate];
NSError *error = nil;
NSArray *fetchedObjects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
if (fetchedObjects == nil) {
return nil;
}
if(fetchedObjects != nil)
{
set = fetchedObjects;
}
return set;
}
The above function when called for any given filter is returning an array with zero objects. I am not able to get why. Any help would be appreciated! Thanks.

Answer 1

You try out this code for searching:-
+(NSArray *)getAllFilterPropertiesForFilter:(Filter *)filter forManagedObjectContext (NSManagedObjectContext *)managedObjectContext
{
NSArray *set = nil;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"FilterProperty" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"belongsToFilter.name == %#", filter.name];
[fetchRequest setPredicate:predicate];
NSError *error = nil;
NSArray *fetchedObjects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
if (fetchedObjects == nil) {
return nil;
}
if(fetchedObjects != nil)
{
set = fetchedObjects;
}
return set;
}

Answer 2

I think in your insertFilterPropertyWithName method you are not saving the new data. If I am correct, try this code after your if-else block:
NSError *error;
if (![managedObjectContext save:&error])
{
//could not save
}
Hope this could resolve your problem.

Answer 3

In that below if condition you need to save in managedobjectcontext.
else if(fetchedObjects != nil && fetchedObjects.count == 0)
{
fp = [NSEntityDescription insertNewObjectForEntityForName:#"FilterProperty" inManagedObjectContext:managedObjectContext];
fp.name = filterPropertyName;
fp.friendlyName = friendlyName;
fp.defaultValue = defaultValue;
fp.minValue = minValue;
fp.maxValue = maxValue;
fp.belongsToFilter = filter;
fp.type = type;
NSError *err = nil;
[managedObjectContext save:&err];
if (errorInWrite != nil) {
//Problem while saving
}
}
Use like instead of "=" Hope it will be useful.
+(NSArray *)getAllFilterPropertiesForFilter:(Filter *)filter forManagedObjectContext (NSManagedObjectContext *)managedObjectContext
{
NSArray *set = nil;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"FilterProperty" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"belongsToFilter.name like %#", filter.name];
[fetchRequest setPredicate:predicate];
NSError *error = nil;
NSArray *fetchedObjects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
if (fetchedObjects == nil) {
return nil;
}
if(fetchedObjects != nil)
{
set = fetchedObjects;
}
return set;
}