title: Approach to change NLS_CHARACTERSET of Oracle 12c Database from US7ASCII to AL32UTF8
body: <p>As a part of Database migration from Oracle 11g to Oracle 12c, we have to change the NLS_CHARACTERSET parameter. 
  Currently Oracle 11g charset is: WE8ISO8859P1 and Oracle 12c charset is US7ASCII. We wish to have Oracle 12c NLS_CHARACTERSET -AL32UTF8.</p>
  
  <p>Our Approach: 
  1) First change charset of 12c to same as 11g, do the import. This import would not result in  data loss since source and  target both have same charset. 
  2)Then we will change Charset to AL32UTF8, run CSSCAN, analyse data loss due to various factors like truncation etc. 
  3) Finally run CSALTER and deal with column width, truncation etc.</p>
  
  <p>Questions I have here are:
  1. CSSCAN is not supported in 12c, what option would help. Can DMU(Database Migration Utility for Unicode) help us here?
  2. CSALTER is also not supported in 12c so what alternative are there?
  3. AL32UTF8 is superset of WE8ISO8859P1, but when we ran CSSCAN on 11g with respect to AL32UTF8, it give us some data loss. Why?
  4.Is there any better approach than this? Please suggest!
  Thanks in advance!</p>