Tab bar controller containing Navigation Bar Problem

Hello,

I am making an iphone application which is having a tab bar controller with 4 tabs. A navigation controller is added on each tab. And these Navigation Controller have table view controller on them.

Once the application is started and i clicked over a particular tab, the very first time, All methods live viewWillAppear and table view delegates (like cellForRowAtIndexPath are called.

But on switching the tab and clicking back on the same tab doesn't call any delegate methods.

The problem is , the table view i want to show read some data from SQLite database. As the delegates are not getting called i am not able to show or pickup the updated data everytime clicking over the tabs.

I have read about this problem a lot. The problem i can found is navigation controller becomes NULL when tab is clicked.

Please help with this problem or provide some alternate way to show my data.

thanks,
Ruhi.