isabella232 / cloudkit-sample-queries

CloudKit Samples: Queries

Goals

This project demonstrates use of CloudKit queries against a CloudKit Private Database. It shows how to filter a set of records by using a predicate against a property — in this case, a set of Contact records with a name property, and a BEGINSWITH predicate to query for records prefixed by a user-provided string.

Prerequisites

• A Mac with Xcode 12 (or later) installed is required to build and test this project.
• An Apple Developer Program membership is needed if you wish to create your own CloudKit container.

Setup Steps

• Ensure the simulator or device you run the project on is signed in to an Apple ID account with iCloud enabled. This can be done in the Settings app.
• If you wish to run the app on a device, ensure the correct developer team is selected in the “Signing & Capabilities” tab of the Queries app target, and a valid iCloud container is selected under the “iCloud” section.

Using Your Own iCloud Container

• Create a new iCloud container through Xcode’s “Signing & Capabilities” tab of the Queries app target.
• Update the containerIdentifier property in Config.swift with your new iCloud container ID.

How It Works

• On first launch, the app fetches all Contact records from the remote database and displays the names of those records in the UI.
• When a user adds a new Contact record through the UI, the record is saved to the remote database and the records are retrieved and displayed again.
• When a user filters the list through the UI, a new query operation is performed using the BEGINSWITH predicate, and only records with the name field beginning with the given filter string are returned and displayed.

Things To Learn

• How to create new records with the CKModifyRecordsOperation.
• How to use CKQuery and CKQueryOperation to build a query matching all or specific records, and retrieve and process the results with a recordFetchedBlock.
• How to use the Result type to provide clear information about the result of asynchronous operations with completion handlers.

Further Reading

• Running Your App in the Simulator or on a Device
• CloudKit Private Database