I still can't see the question. Presumably you wish to take one or more of these opinions for a given strata and use them to categorise or rate or bracket the period(s) that strata is most likely to be a part of, but without you telling us what form those opinions are expressed in, suggesting anything is pretty much impossible.

This link might help others grasp a little of what you are talking about.

Fabulous... thanks for pointing out that link. So, take a look at this http://geology.com/usgs/geologic-time-scale/, or, specifically, at the image at http://geology.com/usgs/geologic-time-scale/geologic-time-scale-one-column-cropped.gif. Now, imagine you have a rock that is estimated to be from between 25 Ma (million years ago) to 20 Ma. So, it started in the Oligocene and ended in the Miocene. The Tertiary period is the "closest" period that completely encompasses the sample rock. So, I want to model the following --

given a point in time or a duration of time, find the closest period that completely encompasses your sample.

Right now we are storing these "periods" with there start and end times in a SQL table, and then doing a lot of nested SQL queries to return our results. I am trying to determine if there are better ways to model such relationships. Intuitively SQL seems wrong for this.



when small people start casting long shadows, it is time to go to bed

Set::IntSpan should do everything you need.

---

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.