Datapump

Use the flashback parameter to export and import a consitent dump

expdp <user>/<pwd> parfile=db_params.par

where db_params.par would look like this:

flashback_time=sysdate
directory=DATAPUMP_DIR
dumpfile=db_schema.dmp
schemas=(apps,test)

This performs a consistent dump of 2 schemas

Keeping the parameters in a file like this allows the possibility to reuse it for the import:

impdp <user>/<pwd> parfile=db_params.par