如何检查CoreData是否为空？

let fetchRequest: NSFetchRequest<NSFetchRequestResult> = YourEntity.fetchRequest()
do {
    let count = try context.count(for: fetchRequest)
    if count == 0 {
        // CoreData is empty
    } else {
        // CoreData is not empty
    }
} catch {
    // Handle error
}

let fetchRequest: NSFetchRequest<YourEntity> = YourEntity.fetchRequest()
fetchRequest.fetchLimit = 1
do {
    let results = try context.fetch(fetchRequest)
    if results.isEmpty {
        // CoreData is empty
    } else {
        // CoreData is not empty
    }
} catch {
    // Handle error
}

if let relatedObjects = yourObject.relatedObjects, !relatedObjects.isEmpty {
    // The relationship is not empty
} else {
    // The relationship is empty
}