sdk-for-apple/docs/examples/databases/decrement-document-attribute.md

import Appwrite

let client = Client()
    .setEndpoint("https://<REGION>.cloud.appwrite.io/v1") // Your API Endpoint
    .setProject("<YOUR_PROJECT_ID>") // Your project ID

let databases = Databases(client)

let document = try await databases.decrementDocumentAttribute(
    databaseId: "<DATABASE_ID>",
    collectionId: "<COLLECTION_ID>",
    documentId: "<DOCUMENT_ID>",
    attribute: "",
    value: 0, // optional
    min: 0, // optional
    transactionId: "<TRANSACTION_ID>" // optional
)