Below is my code i am trying to fetch contain from coredata entity on privatequeue but in return i got null value.
-(NSArray *)fetch_agenda_for_financialdoc:(BOOL)isFinace
{
__block NSArray *fetchRecords;
NSManagedObjectContext *private = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
[private setParentContext:self.managedObjectContext];
[private performBlockAndWait:^{
NSFetchRequest *request = [[NSFetchRequest alloc]init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"AgendaDetails" inManagedObjectContext:private];
[request setEntity:entity];
NSError *error;
fetchRecords = [private executeFetchRequest:request error:&error];
}];
for (AgendaDetails *obj in fetchRecords) {
NSLog(#"%#",obj.agendaName);
}
return fetchRecords;
}
If more detail required i can give you thanks in advance.
Related
Please consider the method at the end of this question. It attempts to delete all records from a CoreData entity.
The first -outcommented- part works fine: it deletes everything from my context, and then saves the context.
The second, non-commented part doesn't seem to work:
As a test I do
NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:#"myEntity"];
NSError *error = nil;
NSArray *results = [self.managedObjectContext executeFetchRequest:request error:&error];
NSLog(#"Fetch request returns %lu objects", (unsigned long)[results count]);
When I add records, and delete all records with the method below, the amount of records only increase.
As far as I understand, it actually works, but the context is not aware of it (yet).
So, therefore, in order to get a reliable context, I should update the context with
[NSManagedObjectContext mergeChangesFromRemoteContextSave:<#(nonnull NSDictionary *)#> intoContexts:self.managedObjectContext];
However, I don't have a clue what I should enter in the (nonnull NSDictionary *) part.
BTW: I only want to use the NSBatchDeleteRequest because I assume it is faster than iterating through all records.
- (void)deleteAllEntities:(NSString *)nameEntity
{
id appDelegate = (id)[[UIApplication sharedApplication] delegate];
self.managedObjectContext= [appDelegate managedObjectContext];
/*
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:nameEntity];
[fetchRequest setIncludesPropertyValues:NO]; //only fetch the managedObjectID
NSError *error;
NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
for (NSManagedObject *object in fetchedObjects)
{
[self.managedObjectContext deleteObject:object];
}
error = nil;
[self.managedObjectContext save:&error];
*/
NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:nameEntity];
NSBatchDeleteRequest *delete = [[NSBatchDeleteRequest alloc] initWithFetchRequest:request];
NSError *deleteError = nil;
}
While fetching data, it returns records with null values (number of records multiply by method call count)
NSManagedObjectContext *context = [self getContext];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Category_List" inManagedObjectContext:context];
[request setEntity:entity];
NSError *error1 = nil;
NSArray *results1 = [context executeFetchRequest:request error:&error1];
NSLog(#"Fetch Request Data Count = %lu", (unsigned long)[results1 count]);
I just call the reset method of the context and my problem is solved.
[context reset];
This question already has an answer here:
Delete objects from NSManagedObjectContext from another method
(1 answer)
Closed 8 years ago.
I need to create a method for my Core Data. This method should check wether there is any results in the entities Section and Fixtures. If there are then delete all og the objects in them.
How can I do this? I've tried this, but does not do anything.
NSManagedObjectContext *context = [self managedObjectContext];
NSManagedObject *numberOfFixtures = [NSEntityDescription
insertNewObjectForEntityForName:#"Fixture"
inManagedObjectContext:context];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Fixture" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
self.theFixtures = [[context executeFetchRequest:fetchRequest error:nil] mutableCopy];
for (numberOfFixtures *fixture in self.theFixtures) {
[context deleteObject:fixture];
}
NSError *error;
[context save:&error];
Try this,
NSManagedObjectContext *context = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Fixture" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
self.theFixtures = [[context executeFetchRequest:fetchRequest error:nil] mutableCopy];
for (NSManagedObject *fixture in self.theFixtures) {
[context deleteObject:fixture];
}
NSError *error;
[context save:&error];
I have two methods,
In first method, I do save values in Core Data, while in other, I simply fetch them.
After inserting, when I fetch data in same method, it shows value, but when I try to fetch in other method if returns me null.
My saving Method is
-(void) saveloginData:(NSString *)facebookTok username:(NSString *)userName password:(NSString*)password flag:(NSString *)flag {
NSError *error;
NSManagedObjectContext *context = [self managedObjectContext];
NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:[NSEntityDescription entityForName:#"SignIn" inManagedObjectContext:context]];
[fetchRequest setIncludesPropertyValues:NO]; //only fetch the managedObjectID
NSString *facebookTokenData = facebookTok;
NSString *usernameData = userName;
NSString *passwordData = password;
NSString *flagData = flag;
NSLog(#"Facebook Token%#\nUsername%#\npassword%#\nflat%#\n",facebookTokenData,usernameData,passwordData,flagData);
SignIn *signIn = [NSEntityDescription
insertNewObjectForEntityForName:#"SignIn"
inManagedObjectContext:context];
signIn.facebookToken = facebookTokenData;
signIn.username = usernameData;
signIn.password = passwordData;
signIn.flag = flagData;
NSEntityDescription *entity = [NSEntityDescription entityForName:#"SignIn"
inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSArray *fetchedArray = [context executeFetchRequest:fetchRequest error:&error];
for (SignIn *info in fetchedArray) {
\\ THis executes and shows values, proves that value are inserted.
NSLog(#"Name ~~~~ : %#", info.username);
NSLog(#"Password ~~~~~~~~ :%#", info.password);
NSLog(#"FLAG ~~~~~~~~~~~ %#",info.flag);
NSLog(#"Facebook Token %#", info.facebookToken);
}
}
My retrieve Method is
-(NSArray*) getLoginData {
NSError *error;
NSManagedObjectContext *context = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"SignIn"
inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSArray *fetchedData = [[NSArray alloc] init];
fetchedData = [context executeFetchRequest:fetchRequest error:&error];
NSLog(#"The count of Array %d", [fetchedData count]); \\ HERE COUNT IS ZERO, WHY?
for (SignIn *info in fetchedData) {
NSLog(#" FF Name ~~~~ : %#", info.username);
NSLog(#"Password ~~~~~~~~ :%#", info.password);
NSLog(#"FLAG ~~~~~~~~~~~ %#",info.flag);
NSLog(#"Facebook Token %#", info.facebookToken);
}
return fetchedData;
}
Please guide that where I am doing mistake.
Your problem is that you need to save conext to get the entity it later.
NSManagedObjectContext save: Attempts to commit unsaved changes to registered objects to their persistent store.
- (BOOL)save:(NSError **)error
Parameters: error: A pointer to an NSError object. You do not need to create an NSError object. The save operation aborts after the first failure if you pass NULL.
Return Value YES if the save succeeds, otherwise NO.
So you need to save context after you modify your object:
signIn.facebookToken = facebookTokenData;
signIn.username = usernameData;
signIn.password = passwordData;
signIn.flag = flagData;
[context save:NULL]; // NULL if you don't need to handle error
I am having some difficulties in deleting an entry from Core Data.
It works but the NSManagedObject data has no values (fault), and so sometimes the wrong entry will be deleted.
In my deleteWholeDatabase method the objects are filled with values.
And in the deleteEntryFromDatabase method are no values. But why?
Here are my methods:
-(NSArray*)databaseRequest{
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:currentEntity inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setReturnsObjectsAsFaults:NO];
NSError *error;
NSArray *items = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
return items;
}
-(void)deleteWholeDatabase{
for (NSManagedObject *objectToDelete in [self databaseRequest]) {
[managedObjectContext deleteObject:objectToDelete];
NSLog(#"%# object deleted",objectToDelete);
}
[self saveContext];
NSLog(#"All entries deleted!");
}
-(void)deleteEntryFromDatabase:(NSManagedObjectContext*)context forEntry:(NSIndexPath*)indexPath{
NSManagedObject *objectToDelete=[[self databaseRequest] objectAtIndex:indexPath.row];
[managedObjectContext deleteObject:[managedObjectContext objectWithID:[objectToDelete objectID]]];
[self saveContext];
NSLog(#"%# deleted!",[managedObjectContext objectWithID:[objectToDelete objectID]]);
}
The wrong entry is being deleted because each request return the itens in a different order. Try deleting the intens by comparing their memory adress
Instead of keeping a calling [self databaseRequest] everywhere, I would keep a local copy of NSManagedObjectID's as an array.
- (void)init {
self.entities = [self databaseRequest];
}
-(NSArray*)databaseRequest{
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:currentEntity inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setReturnsObjectsAsFaults:NO];
NSError *error;
NSArray *items = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
NSMutableArray *itemIDs = [[NSMutableArray alloc] initWithCapacity:[items count]];
for (NSManangedObject *item in items) {
[itemIDs addObject:[item objectID]];
}
return items;
}
Then everywhere where you call [self databaseRequest], you will get an have the correct NSManagedObjectID. Then you just need to get the correct entity from the ID.