I am working on a OWB 11g migration project and we wanted to create external table using OWB 11g. External table is having a column with string data type. So we are expecting this column to be with VARCHAR2(X CHAR), however this is created as VARCHAR2(X BYTE) in OWB 11g. We did not face this issue with OWB 10.1
Solution is to set the init.ora parameter NLS_LENGTH_SEMANTICS to CHAR and restart the database.