title: Associating extra data with a MySQL column
body: <p>I have a typical table, e.g.</p>
  
  <pre><code>id(int) name(varchar) address(varchar) date(datetime)
  </code></pre>
  
  <p>I also have a table that references validation functions for each one, e.g.</p>
  
  <pre><code>id(int) function(varchar) fail_message(varchar)
     1    email             Please enter a valid email address
     2    required          This field can not be left blank
  </code></pre>
  
  <p>I'd like to be able to associate each column from the first table with one or more of these validators.</p>
  
  <p>The only way I can think of doing this is to stuff the ids into the column names e.g. (column name: email;1;2) and keep track of it through PHP, but that seems very messy.</p>
  
  <p>Is there a good way to do this with relational databases? Would a NoSQL implementation suit this problem better?</p>