How to create parent child relationship in Core Data? - core-data

Question

I have dynamic child objects in my JSON response to populate
preferences data, each preference can have "children" and that can
have multiple objects (in nested way, go into details). I need to save
this data into Core data then load from there. Also I need to save
user selection when user selects one on the way.
How to create tables which have parent child relationship? what is the
best way to implement entity relationship in entity model to save all
this data ? Here is my model classes:
class Menu: NSObject {
var active:String?
var code:String?
var desc:String?
var iconId:Int?
var inactive:String?
var isEatin:Int64?
var isTakeAway:Int64?
var menuId:Int?
var menuName:String?
var menuType:Int?
var parentId:Int?
var subMenus:[SubMenu]?
var products:[Product]?
}
class SubMenu: NSObject {
var code:String?
var desc:String?
var eatinPrice:Float?
var isEatin:Int?
var isTakeAway:Int?
var menuId:Int?
var menuName:String?
var menuType:Int?
var parentId:Int?
var sortOrder:Int?
var takeAwayPrice:Float?
var products:[Product]?
}
class Product: NSObject {
var addons:[Addon]?
var modifiers:[Modifier]?
var productImages:[ProductImages]?
var code:String?
var desc:String?
var eatinPrice:Float?
var isDisplayinMenu:Int?
var isEatin:Int?
var isProductset:Int?
var isTakeAway:Int?
var menuId:Int?
var name:String?
var note:String?
var printer:String?
var printerId:Int?
var printerType:String?
var productId:Int?
var rating:Int?
var sortOrder:Int?
var takeAwayPrice:Float?
}
class Addon: NSObject {
var addonsId:Int?
var addonsName:String?
var productId:Int?
var selectionCount:Int?
var addonTypes:[AddonType]?
}
class Modifier: NSObject {
var modifierId:Int?
var modifierName:String?
var productId:Int?
var modifierType:[ModifierType]?
}
class AddonType: NSObject {
var addonTypeId:Int?
var addonTypeName:String?
var price:Float?
var isAddonSelected:Int?
}
class ModifierType: NSObject {
var modifierTypeId:Int?
var modifierTypeName:String?
var isModifierSelected:Int?
}
class AddonModCombo: NSObject {
var addon:[Addon] = [Addon]()
var modifier:[Modifier] = [Modifier]()
var numberOfAddonMod = 1
}

Answer 1

To use Core Data you need to create a data model file-- roughly, a schema. Then your classes must inherit from NSManagedObject. Xcode can automatically create those subclasses for you based on the data model.
Relationships are configured in the data model, and represented as properties of the managed object classes. The result would be similar to your subMenus and products properties, but with a data model and with NSManagedObject.
Apple provides extensive, detailed documentation with sample code and screenshots. For example, relationships are described here: https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CoreData/HowManagedObjectsarerelated.html#//apple_ref/doc/uid/TP40001075-CH17-SW1