CS145 - Spring 2004
Introduction to Databases
Gradiance XPath and XQuery Labs Due Thursday April
29 |
This week, in addition to some regular Gradiance exercises, you will
be using the Gradiance Lab feature again -- this time to perform XPath
and XQuery exercises. The queries you write will be executed over
stored XML documents and checked automatically for correctness. When
you log into Gradiance to complete this week's assignment, you will
need to choose both Lab Projects and Homeworks to
complete your work. Note that you have until Thursday (not Tuesday)
to complete this week's work.
You have two XPath/XQuery Labs to complete: one called
University and one called Auctions. Although both labs
have a mix of queries, we suggest you start with the lab called
University first. Here are some suggestions -- the first is
new, while the second and third are repeats from last week's SQL labs:
- You will probably find XPath and XQuery problems quite
difficult to get absolutely right with the first (or second, or third,
...) try. We suggest you build up your queries in pieces. Obviously
your initial small pieces will not yield correct answers according to
Gradiance, but the answers (or syntax errors!) that you get should
help you build up to that final correct solution.
- Each lab allows you to submit solutions for all of the queries
in the lab at one time. However, we suggest that you work on one
query at a time until you get it correct. The queries in each lab are
ordered roughly from easiest to hardest, but you're welcome to
work on them in any order you like (or all at once if you prefer).
- We strongly suggest that you maintain a separate file
containing the text of your queries as you develop your solutions.
This file may be of use to you during your session, and is especially
important across sessions and in the event that you lose your
Gradiance session for some reason.
As always, your Gradiance work is due at 11:59 PM on the due date, and
no late work is accepted -- the labs will not be available after 11:59
PM on the due date.
Support Materials
Gradiance uses Quip to execute
queries in XPath and XQuery over XML documents. Since XPath and
XQuery are not nearly as mature and standardized as SQL, there are a
number of dialects and quirks. It is VERY IMPORTANT that you
look over our XPath and
XQuery Help Document before getting started, and keep it handy
as you work. You may well tear your hair out if you don't.
Getting Help
If questions or issues arise as you are working with Gradiance, please
contact the course staff at cs145@cs.stanford.edu. The
Gradiance support address (support@gradiance.com) is
NOT to be used for logistical questions about the assignment,
or for technical questions about the XPath/XQuery languages or the
Quip system. Please use the Gradiance support address only in the
case of a major failure of the Gradiance system itself. Even then we
suggest you contact the course staff first, before contacting
Gradiance.
Launch Gradiance to get started.