http://idownvotedbecau.se
http://ideone.com/
http://codepad.org/
http://www.sqlparser.com/document.php
http://107.170.101.241:8080/columnImpact/
http://107.170.101.241:8080/getTableColumn/
https://apex.oracle.com/en/
https://livesql.oracle.com/apex/livesql/file/index.html
http://dba.stackexchange.com/questions/28538/ora-00905-missing-keyword-when-trying-to-create-a-synonym/28570#28570
http://dba.stackexchange.com/questions/33255/factoring-out-subselect-with-clause-ends-in-ora-00904/33482#33482
http://dba.stackexchange.com/questions/47964/ora-01031-while-creating-a-view-as-dba/47996#47996
https://meta.stackoverflow.com/a/252077/754550