Wasn't the original question this:
"Weis & Johnston (2007) assert that the dimension of time is inadequately incorporated in database management systems in general and SQL in particular. Discuss one of authors' supporting reasons for this assertion and why they say it is an important issue. Support your discussion with an example from your current or previous workplace."
Did it not occur to you that identifying the authors for us would be useful information in your question? But Google did turn it up, after a few tries.
You can buy the answer for $20 bucks, see first link.
Or you could read the original Weid/Johnston article (second link), then just 'discuss' it.
I just skimmed the article, but the jist of it seems to be that if you want to know how your data changes over time, then you need some sort of audit trail of those changes over time. We do that on a few tables in our DB at work, but not enough so that we need a grand elaborate scheme to pull it off. We just add inserts into an audit table before doing an update, in those few places we need it.
The $20 answer is probably much better.