title: Scalable one to many table (MySQL)
body: <p>I have a MySQL database, and a particular table in that database will need to be self-referencing, in a one-to-many fashion.  For scalability, I need to find the most efficient solution possible.  The two ways most evident to me are:</p>
  
  <p>1) Add a text field to the table, and store a serialized list of primary keys there</p>
  
  <p>2) Keep a linker table, with each row being a one-to-one.</p>
  
  <p>In case #1, I see the table growing very very wide (using a spatial analogy), but in case #2, I see the linker table growing to a very large number of rows, which would slow down lookups (by far the most common operation).</p>
  
  <p>What's the most efficient manner in which to implement such a one-to-many relationship in MySQL?  Or, perhaps, there is a much saner solution keeping the data all directly on the filesystem somehow, or else some other storage engine?</p>