Core Data relationships, predicates, and delete rules in Xcode | Continued Learning #16
CoreData & Relationships
구현 목표
- 코어 데이터 엔티티 내 릴레이션을 활용하기
- 엔티티 간의 카디널리티(일 대 일, 다 대 일, 일 대 다, 다 대 다) 제약 조건 확인하기
구현 태스크
- 코어 데이터 릴레이션십을 추가한다.
ObservableObject,StateObject선언을 통해 데이터 변경 시 곧바로 UI를 리렌더링한다.- 각 엔티티의 생성 조건에 따라 릴레이션을 추가한다.
핵심 코드
func addDepartment(businessName: String, departmentName: String) {
if !businesses.filter{$0.name == businessName}.isEmpty {
guard let business = businesses.filter{$0.name == businessName}.first else { return }
if departments.filter{$0.name == departmentName}.isEmpty {
let newDeparment = DepartmentEntity(context: manager.context)
newDeparment.name = departmentName
newDeparment.businesses = [business]
if var curDepartments = business.departments {
curDepartments = curDepartments.adding(newDeparment) as NSSet
business.departments = curDepartments
} else {
business.departments = [newDeparment]
}
} else {
guard let curDepartment = departments.filter{$0.name == departmentName}.first else { return }
if var curBusinesses = curDepartment.businesses {
curBusinesses = curBusinesses.adding(business) as NSSet
curDepartment.businesses = curBusinesses
} else {
curDepartment.businesses = [business]
}
}
save()
}
}- 릴레이션에 서로 추가할 엔티티 탐색
- 일 대 일이라면
NSSet인 릴레이션을 그대로 오버라이드 - 다 대 다 혹은 다 대 일, 즉
NSSet릴레이션에 추가해야 할 때adding메소드를 통해 기존 릴레이션에 엔티티를 추가한 새로운NSSet을 생성, 이후 오버라이드
소스 코드
class CoreDataManager {
static let instance = CoreDataManager()
let container: NSPersistentContainer
let context: NSManagedObjectContext
private init() {
container = NSPersistentContainer(name: "CoreDataContainer")
container.loadPersistentStores { description, error in
if let error = error {
print("ERROR LOADING CORE DATA")
print(error.localizedDescription)
} else {
print("SUCCESSFULLY LOADING CORE DATA")
}
}
context = container.viewContext
}
func save() {
do {
try context.save()
} catch {
print("ERROR SAVING CORE DATA")
print(error.localizedDescription)
}
}
}- 코어 데이터를 담당하는 매니저 클래스
- 싱글턴 패턴 구현
class CoreDataRelationshipViewModel: ObservableObject {
let manager = CoreDataManager.instance
@Published var businesses: [BusinessEntity] = []
@Published var departments: [DepartmentEntity] = []
@Published var employees: [EmployeeEntity] = []
init() {
getBusinesses()
getDepartments()
getEmployees()
}
func addBusiness(name: String) {
guard !name.isEmpty else { return }
if businesses.filter{$0.name == name}.isEmpty {
let newBusiness = BusinessEntity(context: manager.context)
newBusiness.name = name
save()
}
}
func addDepartment(businessName: String, departmentName: String) {
if !businesses.filter{$0.name == businessName}.isEmpty {
guard let business = businesses.filter{$0.name == businessName}.first else { return }
if departments.filter{$0.name == departmentName}.isEmpty {
let newDeparment = DepartmentEntity(context: manager.context)
newDeparment.name = departmentName
newDeparment.businesses = [business]
if var curDepartments = business.departments {
curDepartments = curDepartments.adding(newDeparment) as NSSet
business.departments = curDepartments
} else {
business.departments = [newDeparment]
}
} else {
guard let curDepartment = departments.filter{$0.name == departmentName}.first else { return }
if var curBusinesses = curDepartment.businesses {
curBusinesses = curBusinesses.adding(business) as NSSet
curDepartment.businesses = curBusinesses
} else {
curDepartment.businesses = [business]
}
}
save()
}
}
func addEmployee(name: String, age: String, business: String, department: String) {
guard !name.isEmpty && !age.isEmpty && !business.isEmpty && !department.isEmpty, let age = Int16(age) else { return }
guard let business = businesses.filter{$0.name == business}.first, let department = departments.filter{$0.name == department}.first else { return }
guard var curDepartments = business.departments, var curBusinesses = department.businesses, curDepartments.contains(department), curBusinesses.contains(business) else { return }
guard employees.filter{$0.name == name && $0.age == age && $0.business == business && $0.department == department}.isEmpty else { return }
let newEmployee = EmployeeEntity(context: manager.context)
newEmployee.name = name
newEmployee.age = age
newEmployee.department = department
newEmployee.business = business
newEmployee.dateJoined = Date()
if var businessEmployees = business.employees {
businessEmployees = businessEmployees.adding(newEmployee) as NSSet
business.employees = businessEmployees
} else {
business.employees = [newEmployee]
}
if var departmentEmployees = department.employees {
departmentEmployees = departmentEmployees.adding(newEmployee) as NSSet
department.employees = departmentEmployees
} else {
department.employees = [newEmployee]
}
save()
}
func getBusinesses() {
let request = NSFetchRequest<BusinessEntity>(entityName: "BusinessEntity")
do {
self.businesses = try manager.context.fetch(request)
} catch {
print("ERROR FETCHING CORE DATA")
print(error.localizedDescription)
}
}
func getDepartments() {
let request = NSFetchRequest<DepartmentEntity>(entityName: "DepartmentEntity")
do {
self.departments = try manager.context.fetch(request)
} catch {
print("ERROR FETCHING CORE DATA")
print(error.localizedDescription)
}
}
func getEmployees() {
let request = NSFetchRequest<EmployeeEntity>(entityName: "EmployeeEntity")
do {
self.employees = try manager.context.fetch(request)
} catch {
print("ERROR FETCHING CORE DATA")
print(error.localizedDescription)
}
}
func save() {
businesses.removeAll()
departments.removeAll()
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
self.manager.save()
self.getBusinesses()
self.getDepartments()
self.getEmployees()
}
}
}- UI 렌더링을 요청할 수 있도록
@Published로 선언된 로컬 데이터 배열 - 데이터 CRUD 중 생성만 구현
- 비즈니스, 부서, 직원 순서대로 입력 필요
- 비즈니스 : 부서는 서로 다 대 다, 직원은 일 대 일, 직원과 다른 엔티티는 다 대 일 관계의 카디널리티 구현
- 비즈니스는 다른 엔티티 없이 곧바로 생성 가능
- 부서는 해당 비즈니스에 대해서 생성 가능
- 직원은 해당 비즈니스, 부서가 있어야 생성 가능
- 생성 함수
add...에서 현재 코어 데이터 내 저장된 오브젝트에 중복 데이터가 없는지 확인 가능
struct CoreDataRelationshipsBootCamp: View {
@StateObject private var viewModel = CoreDataRelationshipViewModel()
@State private var insertMode: Int = 0
@State private var businessName: String = ""
@State private var departmentName: String = ""
@State private var employeeName: String = ""
@State private var emplyeeAge: String = ""
var body: some View {
NavigationView {
ScrollView {
VStack {
HStack {
Button("Business") {
insertMode = 0
resetTextFieldText()
}
Button("Department") {
insertMode = 1
resetTextFieldText()
}
Button("Employee") {
insertMode = 2
resetTextFieldText()
}
}
switch insertMode {
case 0:
TextField("Add Business Name here...", text: $businessName)
.font(.headline)
.padding(.leading)
.frame(height: 55)
.background(Color.gray.opacity(0.1))
.cornerRadius(10)
.padding(.horizontal)
case 1:
TextField("Add Department Name here...", text: $departmentName)
.font(.headline)
.padding(.leading)
.frame(height: 55)
.background(Color.gray.opacity(0.1))
.cornerRadius(10)
.padding(.horizontal)
TextField("Department's Business", text: $businessName)
.font(.headline)
.padding(.leading)
.frame(height: 55)
.background(Color.gray.opacity(0.1))
.cornerRadius(10)
.padding(.horizontal)
default:
TextField("Add Employee's Name here...", text: $employeeName)
.font(.headline)
.padding(.leading)
.frame(height: 55)
.background(Color.gray.opacity(0.1))
.cornerRadius(10)
.padding(.horizontal)
TextField("Add Employee's Age here...", text: $emplyeeAge)
.font(.headline)
.padding(.leading)
.frame(height: 55)
.background(Color.gray.opacity(0.1))
.cornerRadius(10)
.padding(.horizontal)
TextField("Employee's Business", text: $businessName)
.font(.headline)
.padding(.leading)
.frame(height: 55)
.background(Color.gray.opacity(0.1))
.cornerRadius(10)
.padding(.horizontal)
TextField("Employee's Department", text: $departmentName)
.font(.headline)
.padding(.leading)
.frame(height: 55)
.background(Color.gray.opacity(0.1))
.cornerRadius(10)
.padding(.horizontal)
}
Button {
switch insertMode {
case 0:
viewModel.addBusiness(name: businessName)
case 1:
viewModel.addDepartment(businessName: businessName, departmentName: departmentName)
default:
viewModel.addEmployee(name: employeeName, age: emplyeeAge, business: businessName, department: departmentName)
}
resetTextFieldText()
} label: {
Text("Submit")
.font(.headline)
.foregroundColor(.white)
.frame(height: 55)
.frame(maxWidth: .infinity)
.background(Color.pink)
.cornerRadius(10)
.padding(.horizontal)
}
.padding(.bottom)
ScrollView(.horizontal) {
HStack(alignment: .top) {
ForEach(viewModel.businesses) { business in
BusinesView(entity: business)
}
}
}
ScrollView(.horizontal) {
HStack(alignment: .top) {
ForEach(viewModel.departments) { department in
DepartmentView(entity: department)
}
}
}
ScrollView(.horizontal) {
HStack(alignment: .top) {
ForEach(viewModel.employees) { employee in
EmployeeView(entity: employee)
}
}
}
Spacer()
}
.navigationTitle("Relationships")
}
}
}
func resetTextFieldText() {
businessName = ""
departmentName = ""
employeeName = ""
emplyeeAge = ""
}
}
struct BusinesView: View {
let entity: BusinessEntity
var body: some View {
VStack(alignment: .leading, spacing: 20) {
Text("name : \(entity.name ?? "Default name")")
.bold()
if let departments = entity.departments?.allObjects as? [DepartmentEntity] {
Text("Departments:")
.bold()
ForEach(departments) { department in
Text(department.name ?? "Default name")
}
}
if let employees = entity.employees?.allObjects as? [EmployeeEntity] {
Text("Employees:")
.bold()
ForEach(employees) { employee in
Text(employee.name ?? "Default name")
}
}
}
.padding()
.frame(maxWidth: 300, alignment: .leading)
.background(Color.gray.opacity(0.5))
.cornerRadius(10)
.shadow(radius: 10)
}
}
struct DepartmentView: View {
let entity: DepartmentEntity
var body: some View {
VStack(alignment: .leading, spacing: 20) {
Text("name : \(entity.name ?? "Default name")")
.bold()
if let businesses = entity.businesses?.allObjects as? [BusinessEntity] {
Text("Business")
.bold()
ForEach(businesses) { business in
Text(business.name ?? "Default name")
}
}
if let employees = entity.employees?.allObjects as? [EmployeeEntity] {
Text("Employees:")
.bold()
ForEach(employees) { employee in
Text(employee.name ?? "Default name")
}
}
}
.padding()
.frame(maxWidth: 300, alignment: .leading)
.background(Color.green.opacity(0.5))
.cornerRadius(10)
.shadow(radius: 10)
}
}
struct EmployeeView: View {
let entity: EmployeeEntity
var body: some View {
VStack(alignment: .leading, spacing: 20) {
Text("name: \(entity.name ?? "Default name")")
.bold()
Text("age: \(entity.age)")
.bold()
Text("Date Joined: \(entity.dateJoined ?? Date())")
.bold()
Text("Business:")
.bold()
Text(entity.business?.name ?? "Default name")
.bold()
Text("Department: ")
.bold()
Text(entity.department?.name ?? "Default name")
.bold()
}
.padding()
.frame(maxWidth: 300, alignment: .leading)
.background(Color.blue.opacity(0.5))
.cornerRadius(10)
.shadow(radius: 10)
}
}- UI 담당뷰. 상단 버튼을 통해 현재 입력하는 엔티티 종류를 결정할 수 있다.
구현 화면
JUST DO IT