title: is it good to create index on varchar field containing comma separated values?
body: <p>I was creating a small database which would store good amount of data.
  The table is having a column which will store foreign keys in varchar format (e.g. 1,12,13...) so that I could get the data all in one go.
  So, will it matter if I indexed the column to the primary key of the master table. 
  (I am only indexing and not creating foreign key reference )</p>