地址簿和核心数据 [英] AddressBook and Core Data

问题描述

我试图创建一个应用程序，将存储地址簿联系人的ID使用核心数据的SQLite文件。

I am trying to make an app that will store addressbook contacts' IDs into a SQLite file using core data.

我的问题是，我想要请求一些这些ID是随机的，并且联系人ID是不可靠的，因为在联系人ID中可能有间隙，所以我想有一种索引属性，我可以做我的随机，在索引中永远不会有间隙，如果我删除我的数据库中的一些ID，我想确保索引是重建索引（不确定如果索引是正确的名称，也许一个键）。

My problem is i will want to request some of those IDs at random, and contact IDs is not reliable because there might be gaps in contacts ID, so i want to have a kind of index attribute that i can do my random on that can never have gaps in the indexes, and if i delete some IDs from my data base, i want to make sure that index is reindexed (not sure if index is the right name for that, maybe a key).

数据实现自动？它为我创建的任何数据模型默认创建一个键？如果是这样，我可以访问和利用它吗？如果我删除一行，会发生什么？

Does core data implement that automatically? does it create a key for any data model i create by default? if so, can i access that and take advantage of it? what happens if i delete a row?

对不起，这可能是一个初步问题。

Sorry it might be a preliminary question.

最佳方式更新我的SQLite文件时，地址簿更改与 ABAddressBookRegisterExternalChangeCallback（addressBook，addressBookChanged，* context）？

Also, whats the best way to update my SQLite file when addressbook changes with ABAddressBookRegisterExternalChangeCallback(addressBook, addressBookChanged, *context) ? will i have to rewrite the whole addressbook again to my SQLite?

推荐答案

对于第1部分：

编写一个获取请求，返回所有联系人实体。然后使用 -countForFetchRequest：来确定您有多少。

Write a fetch request that will return all of your Contact entities. Then use -countForFetchRequest: to determine how many you have.

在您的实体范围内生成一个随机整数

Generate a random integer within the range of your entity count.

现在写入另一个获取请求，其中 -fetchOffset 等于随机整数， fetchLimit of 1。

Now write another fetch request with -fetchOffset equal to that random integer, and fetchLimit of 1.

对于第2部分：
ABExternalChangeCallback 不列出任何将指示哪些对象改变的参数。但您可以按 kABPersonModificationDateProperty 对通讯录排序，并查看自上次同步后更改的记录。

For part 2: The documentation for ABExternalChangeCallback doesn't list any parameter that will denote which objects changed. But you could sort the address book by kABPersonModificationDateProperty, and look at records that have changed since the last time you synced up.

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