Tap into your back-office systems.
In many cases, your enterprise app will need to tap into existing back-office systems and data warehouses. While nailing down the user experience on the client application is a top priority for any successful mobile app, the same attention to detail and architecture is required to integrate the client experience with back-end servers. The iOS SDK has a powerful collection of tools and frameworks for storing, accessing, and sharing data resident on corporate data servers.
Web Services
With the iOS SDK, you can work with XML data to communicate between your client application and the server. XML files provide a lightweight, structured format that your app can easily read and write, and they readily fit into the iOS file system. If you’re using SOAP, you can build and parse your own data transactions or use third-party libraries such as gSOAP or Axis2. If you’re implementing REST, you can integrate XML directly into your app to provide increased performance. Learn more about XML web services in iOS
Networking
iOS offers a range of modern, sophisticated, and easy-to-use networking technologies. From the fine-grained control of BSD Sockets, to discovering other devices or computers on a local network with Bonjour, you have many options for accomplishing a wide range of networking tasks. BSD Sockets is the fundamental network programming interface on iOS; all of the higher-level frameworks are based on it. It is a good choice for maximum performance and flexibility. Because BSD is the de-facto standard for UNIX network programming, it is often easy to port networking code over from other platforms. Bonjour is the powerful zero configuration protocol from Apple that makes it easy to find systems and services on a local network automatically. Your application has access to these features through high-level frameworks that make it easy to connect to, render, and interact with information anywhere in the world.
Learn more about networking technologies in iOS.
Local Storage
iOS provides developer frameworks for managing data efficiently. The Core Data framework provides generalized and automated solutions to common tasks associated with object life-cycle and object graph management, including persistence. Core Data provides a general-purpose data management solution developed to handle the data model needs of every kind of application, large or small. Core Data lets you quickly define your application’s 
data model in a graphical way and easily access it from your code. It provides an infrastructure to deal with common functionality such as save, restore, undo and redo, allowing you to get on with the task of building innovation into your application. Because Core Data uses the built-in SQLite data library there is no need to install a separate database system. Learn more about Core Data in iOS