scoec_at_westminster.ac.uk (Michael j Dorey) writes:
>Does anyone on this system have any views/comments etc. on the use of the
>Oracle (SQL) view mechanism? This is a peeve directed to a particular
>lecturer here (who will remain nameless) but who is under the impression
>that when designing a database you should not create views which are
>themselves based (or partly based) on other views. When I questioned 'why?'
>I was given no specific reasoning. The solution to many database problems
>can (of course) be enhanced by using views, and in my view (no pun
>intended!) breaking a complex set of requirements into small
>problem-specific views which may then be linked together into a larger
>view and perhaps to another base table is perfectly logical, and one of the
>plusses of the relational model?? It might also be considered a simple
>extension of functional programming, breaking a problem into specific
>procedures or modules. I would be grateful on any opinions on this - I have
>to add I've seen nothing in any books which discourages it, (in fact it was
>encouraged on a course I attended in 1991) and surely it enhances future
>maintainablity of the system as well???
Well I would not design a system based on a heirarchical system of views. I
would carefully consider my project and find a better way.
I am a firm believer in structured systems. However, structured systems
must balance development time - portability - maintainability - and
performance.
You seem pre-disposed toward your 'view' structure. Such a structure
would most likely perform quite sluggishly. I would reccomend that you take
a step back and consider your position more carefully. I have often times
found myself re-evaluating a circumstance after such an 'objective'
analysis of my own projects.
Ed Henderson
