I don't know if it's the only case, but I know one case where you'll see that is when you use a single bind variable multiple times in the same statement like this: select * from mytable where c1 = :v1 and c2 = :v1; In the trace file, you'll only see the bind value of v1 for bind0 and bind1 will give the "no oacdef" message. Regards, Brandon From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Joe Smith What does this mean in a trace file ________________________________ Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it.