DROP USER SDEV CASCADE; DROP USER STEST CASCADE; DROP USER SPROD CASCADE; DROP USER TDEV CASCADE; DROP USER TTEST CASCADE; DROP USER TPROD CASCADE; CREATE USER SDEV IDENTIFIED by welcome; CREATE USER STEST IDENTIFIED BY welcome; CREATE USER SPROD IDENTIFIED BY welcome; GRANT ALL PRIVILEGES TO SDEV,STEST,SPROD; CREATE USER TDEV IDENTIFIED by welcome; CREATE USER TTEST IDENTIFIED BY welcome; CREATE USER TPROD IDENTIFIED BY welcome; GRANT ALL PRIVILEGES TO TDEV,TTEST,TPROD; CREATE TABLE SDEV.BONUS (ENAME VARCHAR2(10), JOB VARCHAR2(9), SAL NUMBER, COMM NUMBER); CREATE TABLE SDEV.EMP (EMPNO NUMBER(4) NOT NULL, ENAME VARCHAR2(10), J...