# HKSourceQueryDescriptor A query interface that uses Swift concurrency to read the apps and devices that produced the matching samples. ``` struct HKSourceQueryDescriptor where Sample : HKSample ``` ## Overview Use [`HKSourceQueryDescriptor`](/documentation/HealthKit/HKSourceQueryDescriptor) to run a general query that returns a snapshot of all the apps and devices that have saved matching data to the HealthKit store. ```swift // Create the source descriptor. let sourceDescriptor = HKSourceQueryDescriptor(predicate: .workout()) // Read the source data from the HealthKit store. let sources = try await sourceDescriptor.result(for: store) for source in sources { // Process the sources here. print(source) } ``` When you call the descriptor’s [`result(for:)`](/documentation/HealthKit/HKSourceQueryDescriptor/result(for:)) method, it creates and executes an [`HKSourceQuery`](/documentation/HealthKit/HKSourceQuery) in the background, passing the results as an array of [`HKSource`](/documentation/HealthKit/HKSource) instances. ## Topics ### Creating Source Query Descriptors [`init(predicate: HKSamplePredicate)`](/documentation/HealthKit/HKSourceQueryDescriptor/init(predicate:)) Creates a source query descriptor. ### Running Queries [`func result(for: HKHealthStore) async throws -> [HKSource]`](/documentation/HealthKit/HKSourceQueryDescriptor/result(for:)) Runs a one-shot query that asynchronously returns a snapshot of all the sources that saved matching data. ### Accessing Query Properties [`var predicate: HKSamplePredicate`](/documentation/HealthKit/HKSourceQueryDescriptor/predicate) A predicate that limits the data used by the query. ### Default Implementations [HKAsyncQuery Implementations](/documentation/HealthKit/HKSourceQueryDescriptor/HKAsyncQuery-Implementations) ## Relationships ### Conforms To [`HKAsyncQuery`](/documentation/HealthKit/HKAsyncQuery) [`Escapable`](/documentation/Swift/Escapable) [`Copyable`](/documentation/Swift/Copyable) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)