Can we develop iOS App with salesforce SDK , if yes what is the differences between Salesforce and Apple SDK
As to whether you’d want to, I don’t know. You’d be working with third-party frameworks. This runs the risk that: if something doesn’t work, you have to determine whether you got something wrong, Apple got something wrong, or Salesforce got something wrong - that’s twice as many groups who aren’t you to check with. And if Apple change something, you need Salesforce to update their SDK so you can maintain your app. That harms your ability to adapt.
I have been using Salesforce since 2007 and it is not an easy platform to develop on. Their support is not the best and their development forums are not the most helpful. I do have to say that my App which has been in use now for over 7 years has given me no problems what so ever. But it took me over a year and half to develop. But that was due to the many on going changes during the development.
As the gentleman has said, it is not advisable to pursue this hybrid as an App. And if you are successful and something goes wrong. You could be down for weeks while your client has no access to your App. Which would make a very unhappy Client.
The Salesforce Mobile for iOS is an open-source toolkit that provides a collection of native Objective-C libraries and Xcode templates to enable developers to rapidly build iOS appl that securely connect to the Salesforce Platform.
If you are new to Salesforce, so the first step was to get the fundamental knowledge of the platform. If you are interested, in the fundamentals guide and workbooks, these are available on their developer pages. It will be of good help. Also, create your own developer account and familiarize with the platform. Will help with the iOS app too.