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Normally we export oracle database using expdp command. consider Windchill having 3 Organization(Org A,Org B and Org C) are present under site.
is it possible to export oracle data only for Org A ?
I don't think so because it is all in a single Oracle instance and set of data files. When you do a data dump, you do not specify which subset of the Oracle data to dump.
I agree with @BenLoosli.
@vuchekar I am not a Oracle expert, but from WC side I can surely tell you that there is no way/command using you can tell Oracle (from Windchill) which data to export.