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copied!<p>In the software modeling world, this would obviously be done with a class for each species, I.E. "Dog", "Cat", "Fish" which extend "Animal". In the relational database world, this becomes a bit harder to represent.</p> <p>If you wanted to match this object-oriented approach in your database, you would have a table for "Animals" and then a table for each species, "Cat", "Dog", and "Fish". Then you would probably have a species table (or a hard-coded enum in your code) that would give you a value to place in the Animal row for which species each animal was. This would tell you how to look up further information for each animal.</p> <p>This is probably not the best approach. What you have is more what I would call "Custom Data" for each animal. You should define one table that has a list of custom attributes, and another table to match these attributes to a value for each animal row.</p> <p>If you'd like to make it more convenient to see and control which attributes can apply to which species you could make a third table for "Categories" which would link to the Animal species and to a collection of attributes. Then you would specify the category ID on the animal row.</p> <p>Sample tables:</p> <pre><code>Animals ------- ID Age Sex Species Breed Parameters ---------- ID Name Parameter Values ---------------- ParameterID AnimalID Value Categories (optional - add CategoryID to animals) --------------------- ID Name Category Parameters ------------------- CategoryID ParameterID </code></pre>

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