What is the correct statement about the result of difference operation in relational algebra
选项:
A:The result of the difference operation contains all tuples in two relationships, so there may be duplicate tuples
B:The result of the difference operation includes all tuples in two relationships, but there will be no duplicate tuples
C:The result of the difference operation only contains the same tuples in two relationships
D:The result of the "A-B" difference operation consists of tuples that belong to A but not to B
发布时间:2024-04-16 10:08:41