> I have been searching for a method (and here is where I am stumped at
> the terminology to search for!) to dynamically add properties to some
> record.
<snip>
> Any pointers? This must be a problem that has been addressed a number
> of times
Yes, certainly have addressed it a number of times.
With a relational database the only options afaik are:
1. change the underlying structure
2. have a (huge) table containing the attribute values of each entity
separately, with a lookup table of attributes
3. have a finite number of extra user-definable columns in each table
("custom field 1", "custom field 2" etc)
We use 2 in our CMS. I refer to this as "soft metadata" but I don't know
what anyone else calls it. It's the only solution that's generic enough for
our purposes, because we provide an object-oriented data model with a kind
of multiple inheritance. The performance implications need an awful lot of
attention though. If solution 1 is an option, I'd consider it very
carefully.
Some software packages use option 3 rather successfully but it's basically a
kludge, isn't it.
Nick
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