Last few weeks I have been exporting 10g databases for migrating them to 11g. I knew Export Data Pump was read consistent (I have been running into ORA-01555‘s), but I was surprised to see a ORA-02298 (parent keys not found) when importing:

Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/REF_CONSTRAINT
ORA-39083: Object type REF_CONSTRAINT failed to create with error:
ORA-02298: cannot validate (SCOTT.FK_SCALE_ID) - parent keys not found
Failing sql is:
ALTER TABLE "SCOTT"."SCALE_ID" ADD CONSTRAINT "FK_SCALE_ID" FOREIGN KEY ("SCALE_ID") REFERENCES "SCOTT"."SCALE" ("ID") ENABLE

With 10g the Oracle introduce a new parameter FLASHBACK_TIME equivalent to traditional export(exp) consistent parameter.

For 10g the format is : FLASHBACK_TIME="TO_TIMESTAMP('12-JUL-2012 02:14:00', 'DD-MON-YYYY HH24:MI:SS')"
For 11gR2 the format is : FLASHBACK_TIME=systimestamp