A. The constraint commission < salary implies that COMMISSION must be less than SALARY, so it can have a negative value if the salary is greater than zero, making this statement true.
B. The constraint named CR_MGR is listed as a Referential (R) constraint on the MANAGER column, which implies it is a foreign key that would reference the EMPNO column, making this statement true.
C. The SALARY column is part of a Check (C) constraint CC_COMM that requires the SALARY to be greater than 100, which means it must have a value and cannot be NULL, making this statement true.
D. The presence of a foreign key constraint does not automatically create an index on the foreign key column. While Oracle may implicitly create indexes for primary keys, it does not do so for foreign keys.
E. The constraint deptno > 9 prevents DEPTNO from containing values less than or equal to 9, so it cannot contain the value 1, making this statement false.
F. There is no NOT NULL constraint listed on the DEPTNO column in the constraints image, so it can contain NULL values, making this statement false.
G. There is no indication of a unique constraint on the DNAME column in the constraints image; the constraint DNAME IS NOT NULL only implies that the column cannot contain NULL values, making this statement false.
References:
Oracle Database SQL Language Reference, 12c Release 1 (12.1): "Constraints"
Oracle Database Concepts, 12c Release 1 (12.1): "Indexes and Index-Organized Tables"
