which update method is better?

I always use Yast2-online update to update openSUSE 12.1 KDE. some times when i do this, it shows me that there are not any update at current time but at the same time when i use "Software Management >>> Updates" it shows me some updates for applications. and vice versa sometimes Yast2-online update introduce some updates but "Software Management >>> Updates" does not introduce them.
So, What is the difference between these two update methods? Which one is better and more accurate?

I heard something about updating with zipper, how can i do that? is it a replacement for those two methods?

This URL will guide you through, Portal Zypper - openSUSE

BDW, its zypper not zipper. Personally i dont use the update manager or YaST for updates, i disable update manager. Normally update my system through zypper.

Code:

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zypper up

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will update the packages and not change the vendors.

Code:

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zypper dup

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(distribution upgrade) will upgrade the packages to latest one with vendors change if necessary.
You need to become root to use zypper.
You can refer to the above link for how to use zypper in detail.

Which is one accurate and what is the difference: there are loads of articles and posts related to these in this forum. Search for it and you will find it useful.

http://forums.opensuse.org/forums/en...pper-yast.html
http://forums.opensuse.org/search.php?searchid=95754