There were two issues. First there had to be a default for the nil case and second the pick could not be an array. That fixed the problem

The model appears to have not pasted correctly, I used the code block. So here it is again. import SwiftData //Model one: type of contract, i.e. Firm Fixed Price, etc @Model final class TypeOfContract { var contracts: [Contract] @Attribute(.unique) var typeName: String @Attribute(.unique) var typeCode: String var typeDescription: String init(contracts: [Contract], typeName: String = "", typeCode: String = "", typeDescription: String = "") { self.contracts = contracts self.typeName = typeName self.typeCode = typeCode self.typeDescription = typeDescription } } //Model two: the Contract @Model final class Contract { var contractType: TypeOfContract? var costReports: [CostReport] @Attribute(.unique) var contractNumber: String @Attribute(.unique) var contractName: String var startDate: Date var endDate: Date var contractValue: Decimal var contractCompany: String var contractContact: String var contactEmail: String var contactPhone: String var contractNotes: String init(contractType: TypeOfContract? = nil, costReports: [CostReport], contractNumber: String = "", contractName: String = "", startDate: Date = .now, endDate: Date = .now, contractValue: Decimal = 0.00, contractCompany: String = "", contractContact: String = "", contactEmail: String = "", contactPhone: String = "", contractNotes: String = "") { self.contractType = contractType self.costReports = costReports self.contractNumber = contractNumber self.contractName = contractName self.startDate = startDate self.endDate = endDate self.contractValue = contractValue self.contractCompany = contractCompany self.contractContact = contractContact self.contactEmail = contactEmail self.contactPhone = contactPhone self.contractNotes = contractNotes } } //Model Three: The Cost Reports @Model final class CostReport { var contract: Contract? var periodStartDate: Date var periodEndDate: Date var bCWP: Double //Budgeted Cost Work Performed var aCWP: Double //Actual Cost Work Performed var bCWS: Double //Budgeted Cost Work Scheduled //Calculated fields init(contract: Contract? = nil, periodStartDate: Date = .now, periodEndDate: Date = .now, bCWP: Double = 0.0, aCWP: Double = 0.0, bCWS: Double = 0.0) { self.contract = contract self.periodStartDate = periodStartDate self.periodEndDate = periodEndDate self.bCWP = bCWP self.aCWP = aCWP self.bCWS = bCWS } }

Do you know of any examples of such code?

How do I prevent an upsert?

As a note, I removed the unique modifiers on the two fields because I discovered another issue. When I was saving a duplicate field value, it was not failing, it was replacing the current with a new record, thus it remained unique because the old record was replaced.

Here is the model

import SwiftData //Model one: type of contract, i.e. Firm Fixed Price, etc @Model final class TypeOfContract { var contracts: [Contract] var typeName: String var typeCode: String var typeDescription: String init(contracts: [Contract], typeName: String = "", typeCode: String = "", typeDescription: String = "") { self.contracts = contracts self.typeName = typeName self.typeCode = typeCode self.typeDescription = typeDescription } } //Model two: the Contract @Model final class Contract { var contractType: TypeOfContract? var costReports: [CostReport] var contractNumber: String var contractName: String var startDate: Date var endDate: Date var contractValue: Double var contractCompany: String var contractContact: String var contactEmail: String var contactPhone: String var contractNotes: String init(contractType: TypeOfContract? = nil, costReports: [CostReport], contractNumber: String = "", contractName: String = "", startDate: Date = .now, endDate: Date = .now, contractValue: Double = 0.0, contractCompany: String = "", contractContact: String = "", contactEmail: String = "", contactPhone: String = "", contractNotes: String = "") { self.contractType = contractType self.costReports = costReports self.contractNumber = contractNumber self.contractName = contractName self.startDate = startDate self.endDate = endDate self.contractValue = contractValue self.contractCompany = contractCompany self.contractContact = contractContact self.contactEmail = contactEmail self.contactPhone = contactPhone self.contractNotes = contractNotes } } //Model Three: The Cost Reports @Model final class CostReport { var contract: Contract? var periodStartDate: Date var periodEndDate: Date var bCWP: Double //Budgeted Cost Work Performed var aCWP: Double //Actual Cost Work Performed var bCWS: Double //Budgeted Cost Work Scheduled //Calculated fields init(contract: Contract? = nil, periodStartDate: Date = .now, periodEndDate: Date = .now, bCWP: Double = 0.0, aCWP: Double = 0.0, bCWS: Double = 0.0) { self.contract = contract self.periodStartDate = periodStartDate self.periodEndDate = periodEndDate self.bCWP = bCWP self.aCWP = aCWP self.bCWS = bCWS } }

Found the issue: In a one to many relationship to be able to enter the one side of the relationship you need to identify the many side, even if you are not entering any values for the many side. In this case the many side is Contracts and a state variable needs to be declared @State private var contracts: [Contract] = [] with an empty array.

OOPS! forgot the save function let contractType = ContractType() contractType.typeName = typeName contractType.typeCode = typeCode contractType.typeDescription = typeDescription modelContext.insert(contractType) try? modelContext.save() } }

import SwiftData //Model for Earned Value Analysis The Model @Model final class CostReport{ var aCWP: Double //Actual Cost of Work Performed var bCWP: Double //Budgeted Cost of Work Performed var bCWS: Double // Budgeted Cost of Work Scheduled var cumACWP: Double// Cumlative Actual Cost of Work Performed var cumBCWP: Double // Cumlative Budgeted Cost of Work Performed var cumBCWS: Double // Cumlative Budgeted Cost of Work Scheduled var startDateOfPeriod: Date var endDateOfPeriod: Date var contract: Contract? init(aCWP: Double = 0.0, bCWP: Double = 0.0, bCWS: Double = 0.0, cumACWP: Double = 0.0, cumBCWP: Double = 0.0, cumBCWS: Double = 0.0, startDateOfPeriod: Date = .now, endDateOfPeriod: Date = .now, contract: Contract) { self.aCWP = aCWP self.bCWP = bCWP self.bCWS = bCWS self.cumACWP = cumACWP self.cumBCWP = cumBCWP self.cumBCWS = cumBCWS self.startDateOfPeriod = startDateOfPeriod self.endDateOfPeriod = endDateOfPeriod self.contract = contract } } @Model //Model for Contracts final class Contract{ var costReports: [CostReport] var contractType: ContractType? @Attribute(.unique)var contractNumber: String @Attribute(.unique)var contractName: String var startDate: Date var endDate: Date var contractValue: Double var contractorName: String var contractorContact: String var contractorPhone: String var contractorEmail: String init(costReports: [CostReport], contractType: ContractType, contractNumber: String = "", contractName: String = "", startDate: Date = .now, endDate: Date = .now, contractValue: Double = 0.0, contractorName: String = "", contractorContact: String = "", contractorPhone: String = "", contractorEmail: String = "") { self.costReports = costReports self.contractType = contractType self.contractNumber = contractNumber self.contractName = contractName self.startDate = startDate self.endDate = endDate self.contractValue = contractValue self.contractorName = contractorName self.contractorContact = contractorContact self.contractorPhone = contractorPhone self.contractorEmail = contractorEmail } } @Model //Model for contract types final class ContractType{ var contracts: [Contract] @Attribute(.unique)var typeName: String @Attribute(.unique)var typeCode: String var typeDescription: String init(contracts: [Contract], typeName: String = "", typeCode: String = "", typeDescription: String = "") { self.contracts = contracts self.typeName = typeName self.typeCode = typeCode self.typeDescription = typeDescription } } The swiftui code for user entry: ```import SwiftUI import SwiftData struct EnterContractTypes: View { @Environment(\.modelContext) var managedObjectContext @Query private var contracts: [Contract] @Query private var contractTypes: [ContractType] @State private var typeName: String = "" @State private var typeCode: String = "" @State private var typeDescription: String = "" var body: some View { Form { Section(header: Text("Enter Contract Type") .foregroundStyle(Color(.green)) .bold() .font(.largeTitle)) { TextField("Name", text: $typeName) .frame(width: 400, height: 40) TextField("Code", text: $typeCode) .frame(width: 400, height: 40) TextField("Description", text: $typeDescription, axis: .vertical) .frame(width: 600, height: 60) } } .frame(width:1000, height:500) } } Last post used code block but appears to have failed. I did not check it because I was in a hurry, sorry.

Based on your suggestion I found a simple way to accomplish the task. I feed the url for the pdf that is created to Preview which displays the file. From here the user can save the file or print it. Thanks for your help