title: is versus as pl/sql
body: <p>I thought that oracle treats both "is" and "as" same for functions and procedures.I tried googling with "pl/sql is vs as" and got the following link which says both are the same.</p>
  
  <p><a href="https://stackoverflow.com/questions/2338408/is-vs-as-keywords-for-pl-sql-oracle-function-or-procedure-creation">IS vs AS keywords for PL/SQL Oracle Function or Procedure Creation</a></p>
  
  <p>But I found <a href="http://www.adp-gmbh.ch/ora/plsql/coll/declaration.html#index_by" rel="nofollow noreferrer">http://www.adp-gmbh.ch/ora/plsql/coll/declaration.html#index_by</a> which seems to indicate there is a difference. Could somebody (list/point me to a link) the other contexts where using "is/as" makes a difference?.</p>
  
  <p>Thanks.</p>