Core Data Batch insert

Core Data Batch insert

Updated:28.11.2022 20:24 (at the end of this post)

i have 150 rows from entity #1 now i need to insert for each single row from entity #1 (SingleOnes) 20 rows into entity #2 (Packs)

pattern:

row1: count 1, object 1 row2: count 2, object 1 row3: count 3, object 1 (...) row21: count 1, object 2 row22: count 2, object 2 row23: count 3, object 2 and so on 

at the moment i can only do this with creating an array of objects for entity #2 (3000 rows), and save them simply with context.save()

 // sOne:[SingleOnes] // fetched rows from SingleOnes entity // create Packs sOne.forEach { one in for x in 1...20 { let newPack = Packs(context: context) newPack.count = Int16(x) newPack.addToUsedSingleOnes(one) } } context.performAndWait { do { try context.save() } catch let error { print(error.localizedDescription) } } 

but as i have doubts about the reliability of this method i rather want to insert those 3000 rows with a batch insert instead, and i cannot find the right way to do so..

i hand over an array to this function containing all objects from entity #1

 func newBatchInsertSWRequest(with singleOnes: [SingleOnes]) -> NSBatchInsertRequest { var index = 0 let total = singleOnes.count // this is the wrong count and it does not work withs singleOnes.count*20 as well let batchInsert = NSBatchInsertRequest( entity: Packs.entity()) { (managedObject: NSManagedObject) -> Bool in guard index < total else { return true } for x in 1...20 { if let newPack = managedObject as? Packs { let data = singleOnes[index] newPack.count = Int16(x) newPack.addToUsedSingleOnes(data) // (...) } } index += 1 return false } return batchInsert } 

i've tried to many variants of this function but i never managed to create the correct amount of 3000 rows.. any ideas?

Updated:28.11.2022 20:24

 func newBatchInsertWPRequest(with singleOnes: [SingleOnes]) -> NSBatchInsertRequest { var index = 0 let total = 3000 let batchInsert = NSBatchInsertRequest( entity: Packs.entity()) { (managedObject: NSManagedObject) -> Bool in guard index < total else { return true } for x in 1...20 { if let newPack = managedObject as? Packs { let data = singleOnes[index] newPack.count = Int16(x) newPack.addToUsedSingleOnes(data) } index += 1 } return false } return batchInsert } 

Terminating app due to uncaught exception 'NSRangeException', reason: '*** __boundsFail: index 150 beyond bounds [0 .. 149]' terminating with uncaught exception of type NSException 

seems like i can't do it this way...the function expects the amount to be the count of the array given...

i will have to give an array with all 3000 objects to that function.. hm..