IOS. Access to Contacts. 00. overview

1, the mobile device has a very important built-in database-address book, Apple extended it to icloud, so that the Apple device can share contacts between the information.

2, on iOS, the Address Book is placed in the SQLite3 database, but the application is not directly accessible, that is, we write our own application can not use data persistence technology directly to access the Address Book database. To achieve access to the contacts database, Apple has opened some specialized APIs.

3, in security considerations, iOS6 after the application to access the Address Book, need to obtain the user's authorization, and other applications (such as location service authorization), the Address Book is only authorized once for an app, even if the app is removed and reinstalled, do not have to re-authorize.