OCIExecute hangs with invalid sql statement

The following code works fine if passed a valid sql statement in $sql, but if not it hangs. $this->conn=OCIPLogon($orauser,$orapwd,$tns) or die ("Could not log on to database"); $this->stmnt = OCIParse($this->conn, $sql) or die ("Could not initialize database query (parse)"); $result = OCIExecute($this->stmnt) or die ("Could not perform database query (exec)"); I have tried to identify an error at the OCIParse stage, using OCIError, but without success. It seems OCIParse does not return or generate an error for an invalid statement. Instead it returns a statement ID which apparently sends OCIExecute into a coma. Any ideas? Thanks Euan