Who's got an opinion on question 1c - broadly, what is the purpose of doing
an E-R diagram in a database project?
When I look at the mark scheme for this paper, I can't help thinking OCR's
answers are just silly (and wrong),


I think that an E-R diagram is produced:

1) so you can identify the entities in a system, and therefore what tables
you need to include in the database.
2) so you can see how the records in one table will be related to records in
another table, and this can be used as a guide
when setting up foreign keys in tables.
3) so you can compare the database design using an E-R diagram with the
design produced using normalisation, with a view to the design team
discussing and justifying the best approach.
4) so you have a tool (the diagram) that can be used as an aid to discussion
in design team meetings.
5) so that you have a record of the design which can go in the technical
documantation to aid future system maintenance.

Also, my pupils are seriously struggling with the content of this course -
the volume mainly and the lack of time to explore subjects so they
understand them, but also the depth that we seem to need to go in to. They
try hard, but I am beginning to think there is a serious problem with OCR's
computing course. OCR seem totally disinterested in my concerns. Any
opinions on this, or am I alone?

H

By Tim Ault (Tim) on Sunday, May 12, 2002 - 06:12 am:

Could you just clarify - when you say question 1c, what are you referring to?

By Harry on Sunday, May 12, 2002 - 09:38 am:

Apologies. The query concerns the January 2002 exam, Integrated Information Systems.

H

By Tim Ault (Tim) on Monday, May 13, 2002 - 10:32 pm:

I've moved this topic here as most of it refers to 2511.

By YK on Thursday, November 27, 2003 - 01:22 pm:

Hi,

ER diagram, my underderstanding is every entity will be converted to a table or tables (after normalization). But where does the relationship fits in.

Say an ER model of TEACHER teaches STUDENT.

There will be a table for teacher and a table for student. Actually more tables after normalization as it is a Many to Many relationship. But the relationship teaches, where does it fit in the model of an Inforamtion System. Can someone explain this to me.

By Jon on Thursday, November 27, 2003 - 07:00 pm:

Try this:

http://www.theteacher.info/5.4/5.4.6/5.4.6.0/main.html

Jon

By student on Thursday, September 09, 2004 - 05:47 am:

Hi,

What is the realtionship between Data Flow Diagram and ER models produced from the same information system?


thanks

By my opinion on Wednesday, April 27, 2005 - 01:04 pm:

Hi,

I think the OCR Computing syllabus is quite OK. The most demanding part is the project.

Actaully if you look at other Exam Boards, they are not any easier neither.