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2009/04/16

ORA-00932: inconsistent datatypes: expected - got CLOB

As I am doing data query with distinct syntax in select clause, I got this error message:
ORA-00932: inconsistent datatypes: expected - got CLOB

This error message result from Clob limitation:


  1. CLOBs don't work like strings. You can't ask for the LENGTH of a CLOB column, for example. You can work around this with PL/SQL calls but it isn't much fun.
  2. LOBs are not allowed in GROUP BY, ORDER BY, SELECT DISTINCT, aggregates and JOINS


Therefore, I re-designed my database schema. Save this CLOB column into another table.


ORA-01502 Oracle Index in Unusable State

As I execute sql statement to do search, it return this message unexpectedly:ORA-01502: index 'RSDB.RESUME_PK' or partition of such index is in unusable state

Solution: rebuild this index

ALTER INDEX RESUME_PK REBUILD

After I executed this rebuild action, it turned out to be normal.

Reference

[1] http://www.mydigitallife.info/2006/01/28/ora-01502-oracle-index-in-unusable-state/

2009/04/10

2009/04/07

PMD



PMD scans Java source code and looks for potential problems like:
  • Possible bugs - empty try/catch/finally/switch statements
  • Dead code - unused local variables, parameters and private methods
  • Suboptimal code - wasteful String/StringBuffer usage
  • Overcomplicated expressions - unnecessary if statements, for loops that could be while loops
  • Duplicate code - copied/pasted code means copied/pasted bugs
It can be plug-in to Eclipse, NetBeans, etc.

http://pmd.sourceforge.net/

2009/04/06

Utilize Jericho HTML Parser to Resolve NCR Problem

Agenda
  • What is NCR (Numeric Character Reference) ?
  • Scenario Description
  • Problem (XML with NCR)
  • Resolution Process
  • Result (NCR had been decoded)

http://www.slideshare.net/junyuo/utilize-jericho-html-parser-to-resolve-ncr-problem