Global Variables Vs Form Library Package Variables Vs DB Package Variables

Question

I realise this question has been asked a few times with varying degrees of answers, but I am still seeking comment/advice from others.
I am aware of following options for retaining persistent data to share between forms.
1. Package variables in a library that you share in a session.
This requires usage of SHARE_LIBRARY_DATA, there is risk that this not set, then does not share data.
2. Package variables in a database package.
Requires round trip to DB. Is this expensive for performance?
What about risk of DB package becoming invalid and losing state?
3. Use global variables
Can be tricky to manage.
4. Use parameters
Only one way, ie called form cannot alter value that caller can see.
Packages are closest to OO approach in using get and set modules. Allows all variables to be managed in one location. This appears best practice.
Forms library packages appear risky if caller does not include SHARE_LIBRARY_DATA.
DB packages have cost of round trip to DB. Does this become expensive is have to reference many times. Also topic of DB package becoming invalid and losing state?
Forms global variables have regular disadvantages of globals, ie not sure who may modify. Need to manage carefully. Text only
As a second related question, for value such as current user, for performance (and maintainability) is it better to obtain this from oracle user function each time, or save somewhere (in one of options above) and use that saved value each time.

Answer 1

My personal opinion:
I like the "packaged" version with getters and setters. In general, i create a client-side package in a pll which has methods to access the value by getters and setters. With that, the "implementation" is encapsulated and doesn't really matter to the rest of your system. All modules have to access the value using the getter and setter.
Inside the procedure i use two approaches:
1. If its for communication purposes between different forms i use globals, which are filled or extracted in the getter and setter (see this http://andreas.weiden.orcl.over-blog.de/article-28180655.html )
2. If its for someother purpose where the value should be "session persistent" i use a database package with getters and setters, which are called from the client-side package getter and setter. If the value is quite "constant" throughout the session, i read the value once at initialization code of the client-side package and the getter just returns that "cached" value
Hope this helps.