title: Missing Null Keyword Oracle 12C
body: <pre><code>ALTER TABLE READINGS 
       ADD( JSON_COL CLOB 
       CONSTRAINT con_jos_colm CHECK (JSON_COL IS JSON));
  </code></pre>
  
  <p>I'm trying to run this on Oracle 12.1.0.1.0 (which is suppose to support JSON) but getting this error <br></p>
  
  <pre><code>Error report -
  SQL Error: ORA-00908: missing NULL keyword
  00908. 00000 -  "missing NULL keyword"
  *Cause:    
  *Action:
  </code></pre>