title: MySQL - 1 column table
body: <p>So I tried asking this yesterday however my phrasing of the question was pretty terrible. Im stuck designing a database, my system is basically hold different types of creatures, and there are three types of creatures. These are insects, air creatures and aquatic creatures, and so there are three seperate tables for these three. Each of these creatures have a base table and an active table so that a user can get a copy of this base creature. Now I want to be able to reference an id from these tables from another table and Im not sure how besides creating a new table with just an id and then each of these three base creatures having there id being a foreign key of this parent table.</p>
  
  <p>Doing this though would mean that I would have a table which has only one column (ID) that is then referenced from other tables.</p>
  
  <h2>BaseCreatures Table:</h2>
  
  <p>id     </p>
  
  <hr>
  
  <p>1 <br>
  2 <br>
  3 <br>
  4 </p>
  
  <h2>AirCreatures Table:</h2>
  
  <p>id    name </p>
  
  <hr>
  
  <p>1     Eagle <br>
  2     Bird <br></p>
  
  <h2>AquaticCreatures Table:</h2>
  
  <p>id    name</p>
  
  <hr>
  
  <p>3     Whale <br>
  4     Shark</p>
  
  <p>What do you think? Is this ok to do?</p>
  
  <p><a href="https://i.stack.imgur.com/QdNDN.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QdNDN.png" alt="enter image description here"></a></p>
  
  <p>So with a baseAquatic, baseInsect... tables, these store the base stats of that creature. However these havent been assigned to a user yet. In order to do that a new field in the activeCreature needs to be created so that it can generate an id to go in the activeAquatic, activeInsect... tables. The userID is specified in the activeCreatures table and not in the individual active tables. With an active creature it can have special stats that are only applicable to that one, so one activeinsect can have a different strength than another. The activeCreatures is the same as the baseCreatures as they have the same fields barring the userID. Also a basecreature can have a better percentage of appearing in one area than another. (Percentage table), this is the reason why I need to specify the basecreature ids in a seperate table so I can get that to use in the percentage table. Dyou think there is a more efficient way to do this? Another question I have is, on the percentage table, is there really any need for me to store the tableID AND the base id. Couldnt I just store the baseID and then get the id and the tableID from the baseCreatures table. </p>
  
  <p>Another thought is that I could put generic columns such as the creature name in the baseCreatures table as well, but this may get confusing when laying out the information as the name wouldnt be with the other information in the creature specific tables.</p>