From Sergey Linev:

1. Implementation of TDirectory I/O for TSQLFile and TXMLFile
2. In TSQLFile identifier length is now controled.
   Important for Oracle, where table or column name cannot be more than 32 symbols.
3. Adding usage of TSQLStatement class where possible.
4. Small performance improvment.


git-svn-id: http://root.cern.ch/svn/root/trunk@15512 27541ba8-7e3a-0410-8455-c3a389f83636