[2005] how do i get primary key when DataReader is used?

to make the question simple:

what is the counterpart of data adapter's fillschema for datareader because i need to use datatable's find method

Code:

---

....
comd.CommandType = CommandType.StoredProcedure
Using reader As OracleDataReader = comd.ExecuteReader()

Dim dt As New DataTable

dt.Load(reader)

Return dt

End Using
....

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help will be appreciated!