DevOps, CI/CD and Automation

I have a problem with locks.

I try to create a lock thanks to "SELECT X FROM TAB FOR UPDATE NOWAIT".

to do this :
- I parse my query : $resource = ociparse ($onnection, "SELECT X FROM TAB FOR UPDATE NOWAIT") ;
- I execute my query : ociexecute ($resource, OCI_DEFAULT) ;
- I don't close the connection in the script.

If I use the query in SQL*PLUS and (without commit or rollback in SQL*PLUS of course) I start my php script, I obtain the ORA error which tells there is a lock etc... So all is good.

But if I start the script before, and the query in SQL*PLUS after, there is no lock created by the script. Like if there was an implicite rollback.

I don't know if it's a problem of oci, or a problem of configuration or a problem of PHP...

Reproduce code:
---------------
$connect = ociplogon($user, $password,$tns) ;
$resource = ociparse ($connect, "SELECT X FROM TAB FOR UPDATE NOWAIT") ;
ociexecute ($resource, OCI_DEFAULT) ;

Expected result:
----------------
If two scripts are executed at the same time : an oracle error in one of both script.

Actual result:
--------------
No error, and no lock created.