David,
I agree with Kim. Trying to encode information into primary keys is a bit like trying to write a legal contract in chalk on a sidewalk. The contract is washed away next time it rains, the neat looking key order is washed away by errors, species discoveries & reclassifications. The PK doesn't need to mean anything, indeed it shouldn't be made vulnerable to real-world errors of any kind; it's job is strictly logical, as a marker that guarantees row uniqueness and can relate rows in one table to rows in another..
HTH.
PB
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David Blomstrom wrote:
I think my question is more oriented towards PHP, but I'd like to ask it on this list, as I suspect the solution may involve MySQL.
I'm about to start developing an enormous database focusing on the animal kingdom and want to find a key system more user friendly than the traditional scientific name.
So imagine instead a page with the following in the head section:
$AnimalID = 'canlup';
This page displays information on the wolf, based on the first three letters of its genus and species name, Canis lupus.
Now imagine a page with this value:
$AnimalID = 'bal';
This page displays information on the whale family Balaenidae. But what about the whale family Balaenopteridae, which begins with the same three letters?
I could solve this problem by adding a numerical key to my database and displaying the following:
$AnimalID = 'bal23'; $AnimalID = 'bal24';
The problem with this is that it makes it much harder to work with my data. When tweaking a page or writing a script, I can easily remember that bal = Balaenidae, but I can't possibly remember which numeral is associated with each mammal family. Also, what happens if I add or subtract rows from my database table, and the above values suddenly change to bal27 and bal28?
So here's what I think I'd like to do:
$AnimalID = 'canlup1'; $AnimalID = 'bal1'; $AnimalID = 'bal2';
The page with canlup1 will display the FIRST (and only) instance of canlup in the database - the wolf.
The page with bal1 will display the first instance of bal, which will always be Balaenidae, whether the absolute value is bal27 or bal2884. A page with bal2 will always display the next mammal family that begins with bal, Balaenopteridae.
So I THINK all I need to do is create a variable that reflects a particular value's ordinal position in a database... abc1 abc2 abc3, etc.
Plus, I'll have to join two or three fields together to form a key; e.g. animals.species + animals.numerals
Does anyone know how I can do this? Thanks.
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