核心数据如何与托管对象进行交互？

Question

Here is my test code and I can't really understand why print("db2: \\(prod)") writes that my element has attribute belok = 10000 . But I didn't save the context, so in DB there is no changes, it's ok. I'm trying to understand how interact DB and my array arrDBProducts .

var arrDBProducts: [DB_Product]

    func test() {
    let fetchRequest: NSFetchRequest<DB_Product> = DB_Product.fetchRequest()
    do {
        let prods = try CoreDB.context.fetch(fetchRequest)
        for prod in prods {
            print("db1: \(prod)")
        }
    }
    catch {}

    arrDBProducts[0].belok = 10000
    print("array: \(arrDBProducts)")

    let fetchRequest2: NSFetchRequest<DB_Product> = DB_Product.fetchRequest()
    do {
        let prods = try CoreDB.context.fetch(fetchRequest2)
        for prod in prods {
            print("db2: \(prod)")
        }
    }
    catch {}
}

Answer 1

You are didn't save the context, so once you will close and open your app or if you will try to access it from another context - you will not see that changes.

But, while you are working in one context - your changes will exist in it until context will be released.