I have about 20 entity : Event1 ... Event20
In each entity i have property values1 ... values20
I need record data in for example Event5 values8
But something wrong - may be data record in each values8 (Event1 ... Event20)
How do right?
NSString *str = [NSString stringWithFormat:#"Event%d", variable];
NSString *value = [NSString stringWithFormat:#"values%d", vari];
TermometrAppDelegate *app;
app = (TermometrAppDelegate *)[UIApplication sharedApplication].delegate;
NSFetchRequest *fetchRequests = [[NSFetchRequest alloc] init];
NSEntityDescription *entit = [NSEntityDescription entityForName:str inManagedObjectContext:app.managedObjectContext];
[fetchRequests setEntity:entit] ;
[fetchRequests setPropertiesToFetch :[NSArray arrayWithObject:value]];
[fetchRequests setReturnsDistinctResults:YES];
NSError *error;
NSArray *fetchedObject = [app.managedObjectContext executeFetchRequest:fetchRequests error:&error];
NSManagedObject *fetched = nil;
NSManagedObject *fetch = nil;
printf("\n%d", [fetchedObject count]);
The code below retrieves values in Entity5 for Value8 equal to someValueForEight.text (UITextField). This should help you out.
TermometrAppDelegate *app;
app = (TermometrAppDelegate *)[UIApplication sharedApplication].delegate;
NSManagedObjectContext *context = [app managedObjectContext];
NSEntityDescription *entityDesc = [NSEntityDescription entityForName:#"Entity5" inManagedObjectContext:context];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDesc];
NSPredicate *pred = [NSPredicate predicateWithFormat:#"(value8 = %#)", someValueForEight.text];
[request setPredicate:pred];
NSManagedObject *matches = nil;
NSError *error;
NSArray *objects = [context executeFetchRequest:request error:&error];
Related
I find out the User has a sm_owner field. But how do I get the user using sm_owner. My code is like this:
[self.client getLoggedInUserOnSuccess:^(NSDictionary *result) {
NSString *currentLogginedUser = [result valueForKey:#"sm_owner"];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"User" inManagedObjectContext:self.managedOjbectContext];
[request setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"sm_owner like user/%#", currentLogginedUser];
[request setPredicate:predicate];
self.user = [[self.managedOjbectContext executeFetchRequest:request error:nil] objectAtIndex:0];
} onFailure:^(NSError *error) {
}];
And the crash message is:reason: 'Unimplemented SQL generation for predicate (sm_owner LIKE user / "user/test")'
I'm the platform Evangelist for StackMob.
The result from the getLoggedInUserOnSuccess method normally contains primary key "username". So the following code should work.
[self.client getLoggedInUserOnSuccess:^(NSDictionary *result) {
NSString *currentLogginedUser = [result objectForKey:#"username"];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"User" inManagedObjectContext:self.managedOjbectContext];
[request setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"username == %#", currentLogginedUser];
[request setPredicate:predicate];
self.user = [[self.managedOjbectContext executeFetchRequest:request error:nil] objectAtIndex:0];
} onFailure:^(NSError *error) {
}];
Alternatively, if you rather grab the sm_owner from the NSDictionary result. I would do the following.
NSString *sm_owner = [result valueForKey:#"sm_owner"];
NSArray *myArray = [sm_owner componentsSeparatedByString:#"/"];
NSString *currentLogginedUser = [myArray objectAtIndex:1];
Then perform your fetch.
When i am using the NSPredicate while fetch the unique user data from Coredata Entity the app getting crash. But, no error logs. This is the code am using,
if (managedObjectContext == nil)
{
managedObjectContext = [(AppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
}
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"Name==%#",selectedUserName];
NSFetchRequest *fectchreq = [[NSFetchRequest alloc] init];
NSEntityDescription *entitydes = [NSEntityDescription entityForName:#"ALLData" inManagedObjectContext:managedObjectContext];
[fectchreq setEntity:entitydes];
[fectchreq setPredicate:predicate];
NSSortDescriptor *sortdes = [[NSSortDescriptor alloc] initWithKey:#"Name" ascending:YES];
NSArray *sortdesarray = [[NSArray alloc] initWithObjects:sortdes, nil];
[fectchreq setSortDescriptors:sortdesarray];
[sortdes release];
[sortdesarray release];
NSError *error = nil;
//NSMutableArray *storeddata = [[[managedObjectContext executeFetchRequest:fectchreq] error:&error] mutableCopy];
NSArray *storeddata = [managedObjectContext executeFetchRequest:fectchreq error:&error];
//[fectchreq release];
NSLog(#"StoreData : %#, count : %d",storeddata, [storeddata count]);
Can anyone please help to solve this problem? THanks in advance.
NSError *error;
NSMutableArray *storeddata = [managedObjectContext executeFetchRequest:fectchreq error:error];
You need to change this code to:
NSError *error = nil;
NSArray *storeddata = [managedObjectContext executeFetchRequest:fectchreq error:&error];
Reasons:
The error argument should be passed as a pointer because the declaration is -executeFetchRequest:(NSFetchedRequest *)request error:(NSError **)error;
Also this method returns NSArray, not NSMutableArray - you must be getting compiler warning about this...
I'm doing a fetch of data to show it in a UITableView, I do the fetch but I want to sort them by date of creation or by any sort method.
Here is the method:
-(NSArray *) lesStations {
NSManagedObjectContext *moc = [[AppDelegate sharedAppDelegate]managedObjectContext];
NSFetchRequest *fetch = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Station" inManagedObjectContext:moc];
[fetch setEntity:entity];
NSError *error;
NSArray *result = [moc executeFetchRequest:fetch error:&error];
if (!result) {
return nil;
}
return result;
}
This should work
-(NSArray *) lesStations {
NSManagedObjectContext *moc = [[AppDelegate sharedAppDelegate]managedObjectContext];
NSFetchRequest *fetch = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Station" inManagedObjectContext:moc];
[fetch setEntity:entity];
NSError *error;
NSArray *result = [moc executeFetchRequest:fetch error:&error];
if (!result) {
return nil;
}
NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:"creationDate" ascending:YES];
NSArray *sortedResults = [result sortedArrayUsingDescriptors:[NSArray arrayWithObject:sort]];
[sort release];
return sortedResults;
}
You have 2 options: get the results sorted or sort the NSArray with the results:
NSFetchRequest could be set a NSArray of NSSortDescriptor
NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:#"place" ascending:NO]; //the key is the attribute you want to sort by
[fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
You can also sort the returned NSArray (see all instance methods of NSArray starting with sortedArray...)
I suggest using the first approach when working with CoreData. The second one is just informative when working with arrays...
You can sort fetch results by setting sortDescriptors for fetch, e.g.
fetch.sortDescriptors = [NSArray arrayWithObjects:[[NSSortDescriptor alloc] initWithKey: ascending: selector:], nil];
NSError *error;
NSArray *result = [moc executeFetchRequest:fetch error:&error];
I'm trying to get a distinct result from NSPredicate.
My code:
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Members" inManagedObjectContext:context];
request.entity = entity;
request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:#"city"
ascending:YES
selector:#selector(caseInsensitiveCompare:)]];
request.predicate = [NSPredicate predicateWithFormat:#"memberDeleted == %#", [NSNumber numberWithBool:NO]];
NSDictionary *properties = [entity propertiesByName];
request.propertiesToFetch = [NSArray arrayWithObject:[properties objectForKey:#"city"]];
request.returnsDistinctResults = YES;
request.fetchBatchSize = 20;
NSFetchedResultsController *frc = [[NSFetchedResultsController alloc] initWithFetchRequest:request
managedObjectContext:context
sectionNameKeyPath:nil
cacheName:#"CityCache"];
[request release];
self.fetchedResultsController = frc;
[frc release];
The issue is that the result returns many times the same City. This Entity has a lot of Members, and each Member has a property "city".
What am I doing wrong?
Thanks,
RL
Make sure to set the resultType of the NSFetchRequest to NSDictionaryResultType. The default is to return the actual objects, and so it will ignore propertiesToFetch.
With the help of #Alex, here's the final code, without FRC:
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Members" inManagedObjectContext:self.managedObjectContext];
request.entity = entity;
request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:#"city"
ascending:YES
selector:#selector(caseInsensitiveCompare:)]];
request.predicate = [NSPredicate predicateWithFormat:#"memberDeleted == %#", [NSNumber numberWithBool:NO]];
NSDictionary *properties = [entity propertiesByName];
request.propertiesToFetch = [NSArray arrayWithObject:[properties objectForKey:#"city"]];
request.returnsDistinctResults = YES;
request.resultType = NSDictionaryResultType;
request.fetchBatchSize = 20;
NSError *error = nil;
NSArray *tempArray = [self.managedObjectContext executeFetchRequest:request error:&error];
NSMutableArray *cities = [[NSMutableArray alloc] init];
for (int i=0; i < [tempArray count]; i++){
NSDictionary *tempDict = [NSDictionary dictionary];
tempDict = [tempArray objectAtIndex:i];
if ([tempDict objectForKey:#"city"] != nil)
[cities addObject:[tempDict objectForKey:#"city"]];
}
//if the tempArray has no nil values, it's more efficient with:
//NSArray* cities = [tempArray valueForKeyPath:#"city"];
self.cityArray = cities;
[cities release];
[request release];
This returns a NSArray with the list of the Cities.
Thanks.
From the official documentation:
NSManagedObjectContext *context = <#Get the context#>;
NSEntityDescription *entity = [NSEntityDescription entityForName:#"<#Entity name#>" inManagedObjectContext:context];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entity];
[request setResultType:NSDictionaryResultType];
[request setReturnsDistinctResults:YES];
[request setPropertiesToFetch :[NSArray arrayWithObject:#"<#Attribute name#>"]];
// Execute the fetch.
NSError *error;
id requestedValue = nil;
NSArray *objects = [managedObjectContext executeFetchRequest:request error:&error];
if (objects == nil) {
// Handle the error.
}
I want to retrieve a single value (String) from "Entry." I believe I am missing something. Can someone point it out?
XYZAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
NSManagedObjectContext *managedObjectContext = appDelegate.managedObjectContext;
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"name == %#", entryToSearchFor];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Entry" inManagedObjectContext:managedObjectContext];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"name" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[request setSortDescriptors:sortDescriptors];
[request setEntity: entity];
[request setPredicate: predicate];
NSArray *results = [managedObjectContext executeFetchRequest:request error:nil];
if (results == nil) {
NSLog(#"No results found");
}else {
NSLog(#"entryToSearchFor %#", entryToSearchFor);
NSLog(#"results %#", [results objectAtIndex:0]);
}
Btw, the NSLog results outputs the following:
results <NSManagedObject: 0x3d2d360> (entity: Entry; id: 0x3d13650 <x-coredata://6EA12ADA-8C0B-477F-801C-B44FE6E6C91C/Entry/p3> ; data: <fault>)
NSFetchRequest will return an array of NSManagedObjects that matches the request. That is consistent with what you are seeing. Assuming you want to fetch the name, you can do NSLog(#"the name is %#", [[results objectAtIndex:0] name]); to print out the name.