Some problems encountered when importing data from oracle11g to oracle9i

Some problems with importing data from oracle11g to oracle9i when exporting the dmp file from oracle11 and then importing data to oracle9i, there are many errors. To sum up: Problem 1: solution: log in AS sys in the 11g database and modify the exu9defpswitches script, that is, create or replace view exu9defpswitches (compflgs, nlslensem) as select. value, B. value FROM sys. v $ parameter a, sys. v $ parameter B WHERE. name = 'plsql _ code_type 'AND B. name = 'nls _ length_semantics '; then, you can use the exp of the 9.2.0.8 client to export data from the 11g. problem 2: EXP-00008: Oracle error # encounteredORA-01455: converting column overflows integer datatype solution: exp command plus parameter: INDEXES = n STATISTICS = none