exp&imp 优化及版本问题

1、exp用低版本的数据库程序，imp用高版本的数据库程序;

如果是oracle8往oracle7上导，需要在8中执行一个cat7exp.sql脚本，来允许7上的exp在8上导出数据。

Specifies whether Import should commit after each array insert. By default, Import
commits only after loading each table, and Import performs a rollback when an
error occurs, before continuing with the next object.

For tables containingLONG,LOB,BFILE,REF,ROWID,UROWID, orDATE
columns,arrayinsertsarenotdone.IfCOMMIT=y,Importcommitsthesetablesafter
each row.