SwiftUI - Include Relationship info in FetchRequest - swift

Question

I have an Expense entity with a one-to-many relationship to an Accounts Entity.
My current fetch request is as follows:
let request = NSFetchRequest<NSFetchRequestResult>(entityName: Expenses.entity().name ?? "Expenses")
request.predicate = predicate
request.returnsObjectsAsFaults = false
request.resultType = .dictionaryResultType
let expression = NSExpressionDescription()
// check operations list from apple or nshipster in nsexpressions
expression.expression = NSExpression(forFunction: "noindex:", arguments:[NSExpression(forKeyPath: "originAccounts.isCredit")])
expression.name = "checkIsCredit"
expression.expressionResultType = .booleanAttributeType // might be another
let expression1 = NSExpressionDescription()
expression1.expression = NSExpression(forFunction: "noindex:", arguments:[NSExpression(forKeyPath: "id")])
expression1.name = "checkExpenses"
expression.expressionResultType = .UUIDAttributeType
request.propertiesToFetch = [expression,expression1]
context.perform {
do {
let results = try request.execute()
print(results)
My Predicate is:
predicate: NSPredicate(format: "expenseDate >= %# AND expenseDate < %#", datesView.prevMonthPayStart as NSDate, datesView.nextPaydate as NSDate)
When I print the results I get
[{
expenseAccount = "Test Account";
expenseCategory = "Test Category";
expenseCost = 123;
expenseDate = "2020-11-12 05:00:00 +0000";
expenseIsPaid = 1;
expenseName = Test;
expenseType = "One-time";
id = "AFB5EB0E-20A2-47EA-8F36-22D07571C213";
shouldDupe = 1;
}, {
expenseAccount = "Test Account";
expenseCategory = "Test Category";
expenseCost = 23;
expenseDate = "2020-11-13 05:00:00 +0000";
expenseIsPaid = 0;
expenseName = "Test Recurring";
expenseType = Monthly;
id = "5CFB5E58-4377-40DA-9C6A-AF8027ACEC60";
shouldDupe = 1;
}]
I understand that I won't see attributes that are nil, but I want to get an attribute through originAccounts relationship. Is this possible? Specifically I want to get the value of originAccounts.isCredit. Here is an example object for reference.
<Expenses: 0x60000321af80> (entity: Expenses; id: 0xa7ab05bb9341bf4a <x-coredata://ED302202-3018-445F-8FFE-DD2E85219E64/Expenses/p1>; data: {
expenseAccount = "Test Account";
expenseCategory = "Test Category";
expenseCost = 123;
expenseDate = "2020-11-12 05:00:00 +0000";
expenseId = nil;
expenseIsPaid = 1;
expenseName = Test;
expenseType = "One-time";
id = "AFB5EB0E-20A2-47EA-8F36-22D07571C213";
lastMonthlyExpenseID = nil;
nextMonthlyExpenseID = nil;
originAccounts = "0xa7ab05bb9341bf4e <x-coredata://ED302202-3018-445F-8FFE-DD2E85219E64/Accounts/p1>";
originCategories = nil;
shouldDupe = 1;
})

Answer 1

Could you try NSExpressions, you won't make a fetch, therefore you'll be mutch efficient.
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "yourEntity")
fetchRequest.predicate = NSPredicate(format: "yourPredicate")
fetchRequest.resultType = .dictionaryResultType
fetchRequest.returnsObjectsAsFaults = false
let expression = NSExpressionDescription()
// check operations list from apple or nshipster in nsexpressions
expression.expression = NSExpression(forFunction: "yourOperation", arguments:[NSExpression(forKeyPath: "Expenses.originAccounts.isCredit")])
expression.name = "yourName"
expression.expressionResultType = .decimalAttributeType // might be another
fetchRequest.propertiesToFetch = [expression]
do {
let results = try viewContext.fetch(fetchRequest)
print(results)
} catch {
print("Failed to fetch aggregates")
}
}