M359 - Self-Help Session

We had our first 'self-help' session at Saturday. These sessions are rather like the chat you might have over a canteen table at a bricks and mortar university. We get the chance to meet up, talk about what we find difficult on the course, encourage each other and generally help each other out. I find these really useful, especially when I feel that I am stuck. It always useful to get someone else's take on something - perhaps they have a different point of view, perhaps they interpretted something differently. It all helps to widen out the way we think about problems and how we tackle them.

The only problem with these sessions is that so few fellow students turn up. On Saturday there were just three of us. Don't get me wrong, we covered a great deal of ground and it was very useful - but I am sure that other students would benefit too, and the more voices that chime in, the more we all learn.

But it is odd. When I did M206 a couple of years ago we held regular self-help sessions and only three or four people ever turned up for those too. And here's the really odd thing - on previous courses, the people that needed the help and advice the most where the ones who didn't turn up. Explain that!

OU Future Courses

Although I am working towards a Computing Degree, one of the modules that I have been wanting to do was S103 "Introducing Science". I heard towards the end of last year that S103 was being withdrawn and replaced by S104. I thought that I would wait for S104 on the assumption that it would be more up-to-date.

So I was surprised this morning to learn that S104 can not be counted towards my B13 Degree. A dilema! Do I enrol for the last run of S103 starting this September - which screws up my schedule, or do I wait until I have completed my B13 degree by other means (iem by NOT including S103) and then do S104 in a few years time?

Well, if you don't the answer to a question, ask someone who does know! So I contacted the OU this morning. The answer is that S104 CAN be counted towards B13 as the free-choice 60 points because the B13 already has 300 pts of compulsory modules. So it was worth asking! I can do S104 next year as planned after all.

M359 - Conceptual Data Model - problems

Its been a frustrating week. In the course materials we are given a scenario for a University (well, what a surprise!) and a Conceptual Data Model that goes with it. The problem that I have had is that the Entity-Relationship Diagram shows an entity called Staff and another called Course (there are many other entities too). These two entities are linked by a one-to-many 'TelephoneTutoredBy' relationship with the 'one' being at the Course end and the 'many' at the Staff end. My reading of this is that each Course must have one, or more, staff members who do TelephoneTutoring for it. There is also a constraint that says that the staff member doing the telephone tutoring must also tutor at least one enrolment on that course. All pretty straight-forwards.

But the course text then went on to say that a staff member could ONLY telephone tutor on ONE course - and I couldn't see where this was stated in the Conceptual Data Model - there didn't appear to be any constraint anywhere saying that. I raised this as a question on FirstClass. Some responses said that the phrase "...staff member can only be a telephone tutor for a course if they are..." really meant "...a staff member can only tutor for ONE course if they are...". I don't buy the idea that 'a' really means 'one' - its ambiguous. If they had meant 'one' then they would have written 'one', surely. Another respondent suggested that it didn't matter and that I should just ignore the ambiguity (really!). After several days of pondering over this, there was a posting by the conference moderator who had written a guide to interpretting CDM's that went some way towards explaining the situation - but I still felt uneasy.

In the end I think the penny has finally dropped - the Entity-Relationship Diagram is only part of the model. Following the ERD is a list of 'Additional Constraints' that go on to clarify, or complement, the ERD. I think my problem was that I had glossed over the word 'Additional' and had interpretted it as being the textual representation of the diagram (ie; two facets of the same thing - they are not).

Having said that, I still don't see anywhere in the whole Conceptual Data Model where it says that staff can only TelephoneTutor on one course - but I am going to let it lie - the course text clearly make the assumption that it is.

Time to worry about the TMA!