5 Part Keys (OpenInsight 16-Bit)
At 01 OCT 2002 04:28:26PM Mark Glicksman wrote:
Is the use of 4 or 5 part keys an acceptable practice? I've read some of the threads that mention this issue, but don't see a definitive answer.
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At 01 OCT 2002 04:45PM [url=http://www.sprezzatura.com]The Sprezzatura Group[/url] wrote:
Mark - this is quite acceptable. We commonly run 4 part keys for payroll records: client_code*emp_id*paydate*run_id
Also for school timetabling, 5 part keys (in some places):
student*subject*teacher*classroom*timeslot
Always look for ways to employ the internal hierarchies available inside multivalue groups etc. - the use of large keys is often cumbersome, and any efforts to reduce the key size are worthwhile.
There is also the maximum key length limitation to consider.
In your botanical case it might be (and we aren't great gardeners)
phylum*genus*class*species*continent
World Leaders in all things RevSoft
At 02 OCT 2002 09:56AM [url=http://www.sprezzatura.com]The Sprezzatura Group[/url] wrote:
Additionally, indexing on files with keys that long becomes a nightmare as the files get larger. As the number of nodes increase, the time to add a new value can become intolerable. I've seen system where it would take close to 20 seconds to process each new index transaction because of the time it took to balance each branch of the index.
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At 02 OCT 2002 10:30AM Mark Glicksman wrote:
So, it's the length of the key that's more of an issue than how many parts it has? In this case, it's for an Archaeology module, and the proposed key would be SITE (4 char.) * UNIT (12 char.) * LEVEL (sequential integer, 2 place) * CATEGORY (2 char.) * NUMBER (sequential integer starting, maybe 3 or 4 place)
That does add up to quite a long key, doesn't it? Is 16 vs. 32-bit an issue here?
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At 02 OCT 2002 10:47AM [url=http://www.sprezzatura.com]The Sprezzatura Group[/url] wrote:
16/32 has no issue. And yes, it's not the number of parts, it's the length.
There's nothing wrong with mult-part keys. You just have to watch any key as its length starts to increase, be it single part or multi part.
The only place in the system where large keys are an issue is when you are modifying index nodes.
World Leaders in all Things RevSoft
At 02 OCT 2002 02:21PM Mark Glicksman wrote:
Is there a rule of thumb for maximum key length vs. number of records to be indexed?
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At 02 OCT 2002 04:21PM [email protected] wrote:
and of course the repository is built on this type of key structure ..
As for length .. a long time back there was a problem with keys gt 50 characters .. don't know if this was ever addressed but ..
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