Entity Relationship DIagram Query

  • Stuart Rose

    Hello all.

    This is a query for anyone with the Hodder Gibson Practive Papers book.

    I’ve been teaching my pupils to draw an ER diagram with table names inside rectangles, with lines connected between them with the “crow’s foot” end to indicate the one-to-many relationships.

    This was always the case with Higher Information Systems and this is the way SCHOLAR and BBC Bitesize teach the topic. It’s also what the SQA included in the exemplar paper (Q12a answer).

    However, in model paper 2 (section 2, Q2) and model paper 3 (section 2, Q2a answer) the ER diagrams are very different; more complex and much more time consuming to draw.

    So my questions are…

    Do the pupils need to know about this second type of ER diagram?
    What type are they expected to draw if asked in the final exam?
    Are either accepted?

    Peter Thoresen

    The Wikipedia page http://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model describes “Chen’s notation” (as used in H-G papers) in detail, with only one paragraph describing “crow’s foot” notation.

    In the Course Support Notes, Appendix 1 (Reference Documents) includes British Computer Society Glossary of Computing and IT, 12th edition. In the old Higher arrangements it was made clear that BCS Definitions were to be used to avoid confusion – the status of BCS definitions in new Higher is unclear – are they advisory or compulsory?

    BCS Glossary, 13th edition only shows a crow’s foot notation for E-R diagrams.

    As such, I would show pupils some examples of Chen’s notation as an alternative representation of E-R diagrams, but would neither expect pupils to create one nor to understand one in an exam.

    Stuart Rose

    That’s useful. Thanks for your reply.

    Greg Reid

    In the same way that any suitable programming language may be used to answer a software development question, I very much doubt that the SQA would not adopt a similar policy for the variety of ERD notations. Particularly since their is nothing in the new course documentation that states that a single notation will be used.

    The purpose of the exam questions in this area is to asses pupils knowledge of database design concepts. I’m sure the marking schemes will not be specific to a single answer in a single notation.

Viewing 4 posts - 1 through 4 (of 4 total)

You must be logged in to reply to this topic.