Oracle 11i Data Model

After attending Siebel training some time back, this question came up.

In siebel, they have tools in which all the realtions between tables including referential integrity is documented and queried. I understand this is pretty much same is peoplesoft as well.

Oracle 11i model doesn have PK/FK defined for majority of the tables. For example, PO_header_id in po_vendors_all is NOT a primary key, but a check constraint with not null condition. Also there is no PK/FK between po_headers_all and po_lines_all, as defined at the DB level.

For Oracle, I know there are TRMs and I use them a lot. But to my knowledge, there is no "data dictionary" about application tables that would help use derive realtions by querying with in the application.

Is there an approach / method to derive relationships instead of looking at ERDs in TRMs? I guess I am asking is there something equivalent to what Siebel/peoplesoft provide in this area

Thanks in advance

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