Adam,

A> To me, it makes more sense to include a record for each answer, as
A> well as the answer given unless all questions are compulsory (where
A> you could save a bit of data storage).

IMO the structure, or metadata, of a questionnaire should be stored
separately from the answers, or data, otherwise you end up wasting a
lot of space and, more importantly, duplicating information about how
a questionnaire is structured. Perform a left join between metadata
and data to get a NULL for a missing answer.

To make an analogy, storing all 600 rows regardless would be kinda
like storing a table definition once for each record of the table.

A> It may be important to distinguish between the questions that have
A> not been asked and the questions they answered no to.

Of course. That's why I'd store the answer to each question
(yes/no or whatever); a missing row is an answer not given.

Ciao
--
Nando Dessena
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