Join Simon Allardice for an in-depth discussion in this video Using predicates, part of Core Data for iOS and OS X.
So I have code here to create the fetchRequest, to add a sort descriptor object to it and to execute it.…The next step is only fetching specific entities instead of fetching all of them.…So only fetch courses within a certain date range, only fetch employees with the last…name beginning with M, only fetch books where the title includes the word Apple, or only…fetch accounts where the balance is negative.…Now to do this, we use Predicate Objects, and a Predicate will be part of our fetchRequest.…
We will write a Predicate and attach it to the fetchRequest just as we created the SortDescriptor…object and attached that to the fetchRequest.…So I am using the NSPredicate class here, and this is not unique to Core Data.…NSPredicate is part of the regular foundation framework, actually as a SortDescriptor that we just used.…And a Predicate is how you describe something that should be true.…You can think of a Predicate almost as an object that just has the condition part of…an if statement or a while statement, well, in fact it can be a lot more complex than…
- Understanding Core Data and object persistence frameworks
- Creating a Core Data project
- Exploring data modeling
- Creating entities, attributes, and relationships
- Creating managed objects
- Fetching in Core Data
- Implementing undo and redo support
- Creating a Core Data Cocoa app without code
- Responding to validation issues
- Converting store types
- Preloading default data
Skill Level Intermediate
Q: In the CoursesViewController.m file, I receive a message that the method dismissModalViewControllerAnimated is no longer supported by Apple. Is there a newer method to use?
A: You may have received the warning that a call to the dismissModalViewControllerAnimated: method is now deprecated.
This is a recently deprecated method, so the code _will_ continue to work using that call, but to remove the warning, change the code from:
to the current recommended version:
[self dismissViewControllerAnimated:YES completion:nil];
It should take care of that message.
1. Getting Started
2. Modeling in Core Data
3. Saving in Core Data
Creating managed objects12m 46s
4. Fetching in Core Data
Using predicates9m 32s
5. Putting It Together: iOS
6. Putting It Together: Cocoa
7. Store Types and Model Changes
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