Deleting core data objects from a specific section - ios

Question

I have a very weird question, but if I can explain it well, I guess the answer will not be so difficult.
This is my current scenario:
I have a tableView with six fixed sections.
The sections are populated with core data objects.
I am using a transient attribute to decide on which section the object must be shown. This procedure is done in a NSManagedObject subclass. The transient attribute is called sectionIdentifier.
Due to the reason of using a transient attribute to decide on which section should appear every object, I decided to create a special row on each section, with the intention that there will be always at least one row on every section. This option will reduce the problem to have a nil section that would throw exceptions in case of adding or deleting rows, at least this has been a problem sometimes while testing the app.
That means that at the first launch every section has one row (I will call it the special row). And then the user can add/delete rows perfectly.
The problem I have now is that I need this special row to be remove if the section has new rows. At the same time, if the user deletes the last row in the section, the app automatically creates a new special row, so the section is never empty.
I know that this is not the best way to manage it, but due to my iOS knowledge, this is the best way I found to avoid exceptions while adding or removing rows from an empty section.
What I need is to delete the special row from a section when the user has added at least one new row to the section.
The object has a string attribute called quitar and for the special rows: quitar = #"si". This way, all special rows are easy to identify.
I am using this code to delete the special row if there are new rows in the section:
NSManagedObjectContext *context = self.managedObjectContext;
NSEntityDescription *entity=[NSEntityDescription entityForName:#"ToDoItem" inManagedObjectContext:context];
NSFetchRequest *fetch=[[NSFetchRequest alloc] init];
[fetch setEntity:entity];
NSPredicate *predicate=[NSPredicate predicateWithFormat:#"quitar like 'si'"];
[fetch setPredicate:predicate];
NSError *fetchError;
NSArray *fetchedData=[self.managedObjectContext executeFetchRequest:fetch error:&fetchError];
for (NSManagedObject *item in fetchedData){
[context deleteObject:item];
}
I was told that you cannot use transient attributes in a NSPredicate, and you can see in my code, that all special rows are deleted, not only the special from the desired section.
I need your help to find a way to delete only the special row from the section I want, not from all the sections.
Thank you and sorry for my english.
EDITED
Please find below the way I assign sectionIdentifier in the NSManagedObject class ToDoItem:
-(NSString *)sectionIdentifier{
[self willAccessValueForKey:#"sectionIdentifier"];
NSString *tmp = [self primitiveValueForKey:#"sectionIdentifier"];
[self didAccessValueForKey:#"sectionIdentifier"];
if (!tmp){
NSCalendar *calendar = [NSCalendar currentCalendar];
NSInteger comps = (NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit);
NSDate *today = [NSDate date];
NSDate *date = self.todoDueDate;
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setCalendar:calendar];
[components setYear:2065];
[components setMonth:11];
[components setDay:12];
NSDate *dateFuturoSomeday = [calendar dateFromComponents:components];
NSCalendar *calendar1 = [NSCalendar currentCalendar];
NSDateComponents *components1 = [[NSDateComponents alloc] init];
[components1 setCalendar:calendar1];
[components1 setYear:2065];
[components1 setMonth:11];
[components1 setDay:13];
NSDate *dateFuturoCompleted = [calendar1 dateFromComponents:components1];
NSDateComponents *date1Components = [calendar components:comps
fromDate: today];
NSDateComponents *date2Components = [calendar components:comps
fromDate: date];
NSDateComponents *date3Components = [calendar components:comps
fromDate: dateFuturoSomeday];
NSDateComponents *date4Components = [calendar components:comps
fromDate: dateFuturoCompleted];
today = [calendar dateFromComponents:date1Components];
date = [calendar dateFromComponents:date2Components];
dateFuturoSomeday = [calendar dateFromComponents:date3Components];
dateFuturoCompleted = [calendar dateFromComponents:date4Components];
NSInteger daysAfterToday = [calendar components:NSDayCalendarUnit
fromDate:today toDate:date options:0].day;
// NSString *section;
if (daysAfterToday < 0) {
tmp = #"0";
} else if (daysAfterToday == 0) {
tmp = #"1";
} else if (daysAfterToday > 0 && daysAfterToday < 2) {
tmp = #"2";
}
else if ([self.todoDueDate isEqualToDate:dateFuturoSomeday]){
tmp = #"4";
}
else if ([self.todoDueDate isEqualToDate:dateFuturoCompleted]){
tmp = #"5";
}
else {
tmp = #"3";
}
[self setPrimitiveValue:tmp forKey:#"sectionIdentifier"];
}
return tmp;
}

Answer 1

I have checked that at the cellForRowAtIndexPath method, I am able to detect the value from the transient attribute sectionIdentifier. That means that I can use it to identify the special row item, update the value of another attribute an delete it.
ToDoItem *todoitem = [self.fetchedResultsController objectAtIndexPath:indexPath];
NSString *sec = todoitem.sectionIdentifier;
NSString *quitar = todoitem.quitar;
if ([sec isEqualToString:#"1"] && [quitar isEqualToString:#"si" ] && ( numObjectsSec1 > 1 ) ){
NSLog(#"DAS OBJEKT KANN GELÖSCHT WERDEN %#", todoitem.todoName);
NSManagedObjectContext *context = self.managedObjectContext;
[todoitem setValue:#"si se puede borrar" forKey:#"borrar" ];
NSError *error = nil;
// Save the object to persistent store
if (![context save:&error]) {
[context deleteObject: todoitem];
};