Dealing with Core data one-to-many relationship - objective-c

Question

I have been beating my head over this issue for some time now and my last hope is Stack Overflow.
Here is the app idea. I have two entities modeled in core data. The Golfer entity has a one to many relationship with FittingSession, so each golfer is capable of having more than one fitting session. I am not able to post an image for the data models as I am a new user.
But here are the details:
ENTITY: GOLFER and FITTING SESSION
Attributes for Golfer - first_name, last_name, emailId, contactNum, picture
Relationship : NSSet * fittingSessions
Attributes for Fitting Sessions - session_number, date, location, notes.
Relationship: Golfer * whoPlayed
I am working on one view controller called ViewManager (kinda base view for all my classes) and it has 2-3 Custom UIViews inside it. I animate them in and out whenever I need them.
I am getting my Golfers list-collection in a tableview from NSFetchedResultsController and getting the Fitting Sessions attributes in a tableview by the same technique using NSFetchedResultsController. My question is: How do I get a specific fitting session for a specific golfer? What do I have to write in TableViewDidSelectRow Method of Parent( Golfer )View? How do I deal with this one to many relationship? Here's my code:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
if(tableView == mGolferTblView)
{
NSInteger count = [[self.fetchedResultsController sections] count];
NSLog(#"count section GOLFER TABLE VIEW=%d", count);
return count;
}
else if(tableView == mFittingTblView)
{
return 1;
}
else {
}
return 0;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if(tableView == mGolferTblView)
{
id<NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
NSLog(#"count for array ROWS for GOLFERS =%d", [sectionInfo numberOfObjects]);
return [sectionInfo numberOfObjects];
}
else if(tableView == mFittingTblView)
{
mFittingSessionArray = [mFittingSessionSet allObjects];
NSLog(#"array here is=%#", mFittingSessionArray);
NSLog(#"count for ROWS in FITTING SESSIONS table view=%d", [mFittingSessionArray count]);
return [mFittingSessionArray count];
// id<NSFetchedResultsSectionInfo> sectionInfo = [[self.fittingFetchedResultsController sections] objectAtIndex:section];
// NSLog(#"count for array ROWS for FITTING SESSIONS =%d", [sectionInfo numberOfObjects]);
// return [sectionInfo numberOfObjects];
}
else {
}
return 0;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if(tableView == mGolferTblView)
{
static NSString *CellIdentifier = #"Cell";
static NSInteger fullNameTag = 1;
static NSInteger imageTag = 2;
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleGray;
UILabel *fakeLbl =[[UILabel alloc] initWithFrame:CGRectMake(100, 30, 100, 30)];
fakeLbl.backgroundColor = [UIColor clearColor];
fakeLbl.textColor = [UIColor grayColor];
fakeLbl.text=#"3 days ago";
[cell.contentView addSubview:fakeLbl];
[fakeLbl release];
UIImageView *btnImage =[[UIImageView alloc] initWithFrame:CGRectMake(250, 40, 25, 28)];
btnImage.image = [UIImage imageNamed:#"badge_25x28.png"];
btnImage.contentMode = UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:btnImage];
[btnImage release];
UILabel *fullNameLbl =[[UILabel alloc] initWithFrame:CGRectMake(100, 0, 300, 30)];
fullNameLbl.backgroundColor = [UIColor clearColor];
fullNameLbl.textColor = [UIColor whiteColor];
fullNameLbl.numberOfLines = 1;
fullNameLbl.adjustsFontSizeToFitWidth = YES;
fullNameLbl.tag = fullNameTag;
[cell.contentView addSubview:fullNameLbl];
[fullNameLbl release];
UIImageView *imageView =[[UIImageView alloc] initWithFrame:CGRectMake(10, 5, 71, 91)];
imageView.backgroundColor = [UIColor clearColor];
imageView.tag = imageTag;
[cell.contentView addSubview:imageView];
[imageView release];
}
mGolfer = [self.fetchedResultsController objectAtIndexPath:indexPath];
UILabel * fullNameLbl = (UILabel *) [cell.contentView viewWithTag:fullNameTag];
fullNameLbl.text = mGolfer.fullName;
UIImageView * imgView = (UIImageView *) [cell.contentView viewWithTag:imageTag];
imgView.image = mGolfer.picture;
return cell;
}
if(tableView == mFittingTblView)
{
static NSString *CellIdentifier = #"Cell";
static NSInteger locationTag = 1;
static NSInteger notesTag = 2;
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleGray;
UIImageView *iconImage =[[UIImageView alloc] initWithFrame:CGRectMake(10, 40, 11, 18)];
iconImage.image = [UIImage imageNamed:#"icon_locationmarker_11x18.png"];
iconImage.contentMode = UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:iconImage];
[iconImage release];
UILabel *fakeDateLbl =[[UILabel alloc] initWithFrame:CGRectMake(180, 15, 100, 20)];
fakeDateLbl.backgroundColor = [UIColor clearColor];
fakeDateLbl.textColor = [UIColor grayColor];
fakeDateLbl.text=#"apr.30.2012";
[cell.contentView addSubview:fakeDateLbl];
[fakeDateLbl release];
UIImageView *fakeImage1 =[[UIImageView alloc] initWithFrame:CGRectMake(25, 90, 43, 43)];
fakeImage1.image = [UIImage imageNamed:#"icon_catDriver_43x43.png"];
fakeImage1.contentMode = UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:fakeImage1];
[fakeImage1 release];
UIImageView *fakeImage2 =[[UIImageView alloc] initWithFrame:CGRectMake(70, 90, 43, 43)];
fakeImage2.image = [UIImage imageNamed:#"icon_catFairway_43x43.png"];
fakeImage2.contentMode = UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:fakeImage2];
[fakeImage2 release];
UIImageView *fakeImage3 =[[UIImageView alloc] initWithFrame:CGRectMake(115, 90, 43, 43)];
fakeImage3.image = [UIImage imageNamed:#"icon_catHybrid_43x43.png"];
fakeImage3.contentMode = UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:fakeImage3];
[fakeImage3 release];
UIImageView *fakeImage4 =[[UIImageView alloc] initWithFrame:CGRectMake(160, 90, 43, 43)];
fakeImage4.image = [UIImage imageNamed:#"icon_catIron_43x43.png"];
fakeImage4.contentMode = UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:fakeImage4];
[fakeImage4 release];
UIImageView *fakeImage5 =[[UIImageView alloc] initWithFrame:CGRectMake(205, 90, 43, 43)];
fakeImage5.image = [UIImage imageNamed:#"icon_catWedge_43x43.png"];
fakeImage5.contentMode = UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:fakeImage5];
[fakeImage5 release];
UILabel *sessionLbl =[[UILabel alloc] initWithFrame:CGRectMake(10, 7, 150, 30)];
sessionLbl.backgroundColor = [UIColor clearColor];
sessionLbl.textColor = [UIColor redColor];
sessionLbl.text = #"session";
sessionLbl.font = [UIFont boldSystemFontOfSize:18];
[cell.contentView addSubview:sessionLbl];
[sessionLbl release];
UILabel *locationLbl =[[UILabel alloc] initWithFrame:CGRectMake(30, 32, 270, 30)];
locationLbl.backgroundColor = [UIColor clearColor];
locationLbl.textColor = [UIColor whiteColor];
locationLbl.tag = locationTag;
[cell.contentView addSubview:locationLbl];
[locationLbl release];
UILabel *notesLbl =[[UILabel alloc] initWithFrame:CGRectMake(30, 54, 270, 30)];
notesLbl.backgroundColor = [UIColor clearColor];
notesLbl.textColor = [UIColor whiteColor];
notesLbl.tag = notesTag;
[cell.contentView addSubview:notesLbl];
[notesLbl release];
}
mFittingSessionArray = [mFittingSessionSet allObjects];
mFittingSession = [mFittingSessionArray objectAtIndex:indexPath.row];
UILabel *locationLbl = (UILabel *)[cell.contentView viewWithTag:locationTag];
locationLbl.text = mFittingSession.locationUppercase;
NSLog(#"location=%#", mFittingSession.locationUppercase);
UILabel *notesLbl = (UILabel *)[cell.contentView viewWithTag:notesTag];
notesLbl.text = mFittingSession.notesInQuotes;
return cell;
}
return 0;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if(tableView == mGolferTblView)
{
mGolfer = (Golfer *)[self.fetchedResultsController objectAtIndexPath:indexPath];
mGolferNameLbl.text = mGolfer.fullName;
mGolferHeaderPicture.image = mGolfer.picture;
NSSet * fittingSessionSet = mGolfer.fittingSessions;
mFittingSessionArray = [fittingSessionSet allObjects];
NSLog(#"count for sessions=%d", [mFittingSessionArray count]);
NSLog(#"fiting sessions for golfer %# are= %#", mGolfer.first_name, mFittingSessionArray);
}
}
Also, this is how I add a new fitting session to a particular golfer:
- (IBAction)addNewSession:(id)sender
{
AppDelegate * applicationDelegate = (AppDelegate *) [[UIApplication sharedApplication] delegate];
NSManagedObjectContext * context = [applicationDelegate managedObjectContext];
mFittingSession=(FittingSession*) [NSEntityDescription insertNewObjectForEntityForName:#"FittingSession" inManagedObjectContext:context];
mFittingSession.location=mLocationTextField.text;
mFittingSession.notes=mNotesTxtView.text;
**mFittingSession.whoPlayed = self.golfer;** This is setting the relationship (whoPlayed is inverse relation to golfer provided by core data)
}
Please help me in this as I am really not getting how to deal with the relationship in core data. Please provide some code or snippets so that I can know what's going on.
Thank you

Answer 1

Maybe I don't understand your question correctly, but to get a Golfer's Fitting Session is really easy. So in the first code block you just do the following:
mGolfer = (Golfer *)[self.fetchedResultsController objectAtIndexPath:indexPath];
NSSet *fittingSession = mGolfer.fittingSessions;
You can access the relations as you would access the other attributes.

Answer 2

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
if(tableView == mGolferTblView)
{
NSInteger count = [[self.fetchedResultsController sections] count];
NSLog(#"count section GOLFER TABLE VIEW=%d", count);
return count;
}
else if(tableView == mFittingTblView)
{
NSInteger countOfSections = 1;
NSLog(#"count section FITTING SESSION VIEW=%d", countOfSections);
return countOfSections;
}
else {
}
return 0;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if(tableView == mGolferTblView)
{
id<NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
NSLog(#"count for ROWS in GOLFERS table view =%d", [sectionInfo numberOfObjects]);
return [sectionInfo numberOfObjects];
}
else if(tableView == mFittingTblView)
{
mFittingSessionArray = [mFittingSessionSet allObjects];
NSLog(#"array here is=%#", mFittingSessionArray);
NSLog(#"count for ROWS in FITTING SESSIONS table view=%d", [mFittingSessionArray count]);
return [mFittingSessionArray count];
}
else {
}
return 0;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if(tableView == mGolferTblView)
{
static NSString *CellIdentifier = #"Cell";
static NSInteger fullNameTag = 1;
static NSInteger imageTag = 2;
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleGray;
UILabel *fullNameLbl =[[UILabel alloc] initWithFrame:CGRectMake(100, 0, 300, 30)];
fullNameLbl.backgroundColor = [UIColor clearColor];
fullNameLbl.textColor = [UIColor whiteColor];
fullNameLbl.numberOfLines = 1;
fullNameLbl.adjustsFontSizeToFitWidth = YES;
fullNameLbl.tag = fullNameTag;
[cell.contentView addSubview:fullNameLbl];
[fullNameLbl release];
UIImageView *imageView =[[UIImageView alloc] initWithFrame:CGRectMake(10, 5, 71, 91)];
imageView.backgroundColor = [UIColor clearColor];
imageView.tag = imageTag;
[cell.contentView addSubview:imageView];
[imageView release];
}
mGolfer = [self.fetchedResultsController objectAtIndexPath:indexPath];
UILabel * fullNameLbl = (UILabel *) [cell.contentView viewWithTag:fullNameTag];
fullNameLbl.text = mGolfer.fullName;
UIImageView * imgView = (UIImageView *) [cell.contentView viewWithTag:imageTag];
imgView.image = mGolfer.picture;
return cell;
}
else if(tableView == mFittingTblView)
{
**mFittingSessionArray = [mFittingSessionSet allObjects];** // Added this line
static NSString *CellIdentifier = #"Cell";
static NSInteger locationTag = 1;
static NSInteger notesTag = 2;
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleGray;
UILabel *locationLbl =[[UILabel alloc] initWithFrame:CGRectMake(30, 32, 270, 30)];
locationLbl.backgroundColor = [UIColor clearColor];
locationLbl.textColor = [UIColor whiteColor];
locationLbl.tag = locationTag;
[cell.contentView addSubview:locationLbl];
[locationLbl release];
UILabel *notesLbl =[[UILabel alloc] initWithFrame:CGRectMake(30, 54, 270, 30)];
notesLbl.backgroundColor = [UIColor clearColor];
notesLbl.textColor = [UIColor whiteColor];
notesLbl.tag = notesTag;
[cell.contentView addSubview:notesLbl];
[notesLbl release];
}
mFittingSession = [mFittingSessionArray objectAtIndex:indexPath.row];
UILabel *locationLbl = (UILabel *)[cell.contentView viewWithTag:locationTag];
UILabel *notesLbl = (UILabel *)[cell.contentView viewWithTag:notesTag];
locationLbl.text = mFittingSession.locationUppercase;
notesLbl.text = mFittingSession.notesInQuotes;
return cell;
}
else {
}
return 0;
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if(tableView == mGolferTblView)
{
if(self.editing)
{
[self.golferTblView deselectRowAtIndexPath:indexPath animated:YES];
[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseOut
animations:^ {
mEditGolfersView.hidden = NO;
mEditGolfersView.frame = CGRectMake(305, mEditGolfersView.frame.origin.y, mEditGolfersView.frame.size.width, mEditGolfersView.frame.size.height);
}
completion:NULL];
mGolfer = (Golfer *) [self.fetchedResultsController objectAtIndexPath:indexPath];
mEditFirstName.text = mGolfer.first_name;
mEditMiddleName.text = mGolfer.middle_name;
mEditLastName.text = mGolfer.last_name;
mEditEmailField.text = mGolfer.email_id;
mEditContactNum.text = mGolfer.contactNumber;
mEditPictureView.image = mGolfer.picture;
mShowDataBtn.enabled = NO;
return;
}
[self.golferTblView deselectRowAtIndexPath:indexPath animated:YES];
[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseOut
animations:^ {
mGolfersView.frame = CGRectMake(-260, mGolfersView.frame.origin.y, mGolfersView.frame.size.width, mGolfersView.frame.size.height);
}
completion:^(BOOL finished){
mGolfersView.hidden = YES;
}];
[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseIn
animations:^ {
mFittingSessionView.hidden = NO;
mFittingSessionView.frame = CGRectMake(-19, mFittingSessionView.frame.origin.y, mFittingSessionView.frame.size.width, mFittingSessionView.frame.size.height);
}
completion:NULL];
mGolfer = (Golfer *)[self.fetchedResultsController objectAtIndexPath:indexPath];
mGolferNameLbl.text = mGolfer.fullName;
mGolferHeaderPicture.image = mGolfer.picture;
mFittingSessionSet = mGolfer.fittingSessions;
mFittingSessionArray = [mFittingSessionSet allObjects];
NSLog(#"count for sessions=%d", [mFittingSessionArray count]);
NSLog(#"fiting sessions for golfer %# are= %#", mGolfer.first_name, mFittingSessionArray);
**[mFittingTblView reloadData];** // Added this and this reloads the data for fitting view.
}
}