can not view attribute table of a oracle spatial layer

I have an oracle spatial user which I have registered as geodatabase using ‘SDESETUP’ command. Then I have registered couple of tables from the user as ARCSDE layers using ‘SDELAYER’ command successfully. Then I have made a spatial connection in ARCMAP for the user and added those tables as layers in TOC. Although I can view the geometries, when I right-click on the layer and try to open the attribute table, it does not display the rows. The tables has got at least 500 rows.
Any help would be greatly appreciated.