I would like to make predicate more flexible for changes. I have lot of such strings in the sources code:
let predicate = NSPredicate(format: "bodyPart.name = %#", name)
let filteredExercises = ExerciseEntity.mr_findAll(with: predicate)
but as you see if I will change BodyPart name to MuscleGroup for example someday it will cause issue like:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'keypath bodyPart.name not found in entity <NSSQLEntity ExerciseEntity id=5>'
I am searching for the solution with a key paths like
let predicate = NSPredicate(format: "%# = %#", \BodyPart.name, name)
Use %K to substitute the key path
let predicate = NSPredicate(format: "%K = %#", #keyPath(BodyPart.name), name)
Related
My Entity Office have set of File entities. Each File has uuid property. I need to fetch offices where we have any file where UUID is not in set of Strings
I tried to use
let predicate = NSPredicate(format: "NOT (ALL files.uuid IN %#)", uuidSet)
let predicate = NSPredicate(format: "ANY files.uuid NOT IN %#", uuidSet)
let predicate = NSPredicate(format: "ANY NOT files.uuid IN %#", uuidSet)
I always get the error like
exception 'NSInvalidArgumentException', reason: 'Unsupported predicate NOT ALL files.uuid IN {"C0DF0E67-ED8A-4D3B-87A1-E4E7B86967AA"}'
Is there a way to write this Predicate properly? Because right now I only see the solution to load all offices and then iterate through every item.
after migration to swift3, I have an issue that cannot fix
let fetchRequest: NSFetchRequest<User> = User.fetchRequest()
fetchRequest.predicate = NSPredicate(format: "id == %#", id)
my App crashes on second line, bad access, no reason. types are right, no log, nothing, just bad access. any suggestions?
Found a reason, predicate is wrong, cause id is Int64 type, have no idea what kind of predicate I need for this version of swift
The %# format expect a Foundation object as argument, compare
"Predicate Format String Syntax" in the "Predicate Programming Guide".
You can bridge the Int64 to NSNumber:
let id = Int64.max
let predicate = NSPredicate(format: "id == %#", id as NSNumber)
print(predicate) // id == 9223372036854775807
or change the format to "long long":
let id = Int64.max
let predicate = NSPredicate(format: "id == %lld", id)
print(predicate) // id == 9223372036854775807
Bridging all number types to NSNumber is possible as of Swift 3.0.1 (Xcode 8.1) with the implementation of
SE-0139 Bridge Numeric Types to NSNumber and Cocoa Structs to NSValue.
I am facing an odd error with my code:
if let date = self.messages.last?.date {
let newMessages = self.realm.objects(Message).filter("chatId == '\(self.chatId!)' AND date > \(date)")
}
This outputs the error:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to parse the format string "chatId = 'oSgUGWH9fWURmBh5NQZK2POpxdI3yEdl7PrPzAU33l7cVFIpzR38otF3' AND date > 2016-07-17 10:56:07 +0000"'
What am I doing wrong?
EDIT:
Using NSPredicate it works:
let predicate = NSPredicate(format: "chatId = %# AND date > %#", self.chatId!, date)
newMessages = self.realm.objects(Message).filter(predicate)
But why doesn't the first solution work?
If you want to filter an array using a predicate, you need to pass a predicate and not just a string literal as the argument, and also use the method filteredArrayUsingPredicate(_:).
Why "chatId == '\(self.chatId!)' AND date > \(date)" doesn't work is that the compiler interprets this as a string literal - and not a predicate as you've created in your other example:
NSPredicate(format: "chatId = %# AND date > %#", self.chatId!, date)
The fix is to either instantiate an NSPredicate as you've done in your edit, and pass that value to filteredArrayUsingPredicate(:_) or just move the instantiation to inside the method:
newMessages = self.realm.objects(Message).filteredArrayUsingPredicate(NSPredicate(format: "chatId = %# AND date > %#", self.chatId!, date))
If you want to use this method, the array needs to be an NSArray, and the objects in the array need to be KVC compliant, so you're better off in Swift with using the filter(_:) method as such:
let newMessages = self.realm.objects(Message).filter({ $0.chatId == self.chatId! && $0.date.compare(date) == NSComparisonResult.OrderedDescending })
I want to show all items where value1 contains value2. I tried this:
let fetchRequest = NSFetchRequest(entityName: "Product")
fetchRequest.predicate = NSPredicate(format: "value1 CONTAINS[cd] value2")
value1, value2 - current object values, it is not variables
But i got error:
Unable to parse the format string
Why it doesn't allow me to do this ?
Try to use this predicate:
let predicate = NSPredicate(format: "value1 CONTAINS[cd] %#", value2)
As were investigated during communication with developer. Issue is in data that is saved to the database. In his case data is saved with quotes ("") and NSPredicate(format: "value1 CONTAINS[cd] %#", value2) is working with errors due to that issue.
I get the following problem:
'NSInvalidArgumentException', reason: 'Unable to generate SQL for predicate (category == Basis) (problem on RHS)'
case "Basisfragen":
request.predicate = NSPredicate(format: "category = Basis")
break
Does anybody have an idea why it doesn't work?
Wasn't able to find a helpful answer for Swift or to translate any Objective-C answer to a working one in Swift...
Thx!
Patrick
use this that assume that category is a key or attribute with string type.
request.predicate = NSPredicate(format: "category ==%#","Basis")