DBI202Xuất hiện trong 1 đề thi
Given two relations and its data: Student (ID, NAME) | ID | NAME | |---|---| | 1 | a | | 2 | b | Enroll (ID, COURSE) | ID | COURSE | |---|---------| | 1 | Math | | 1 | Physical| | 2 | Math | In relational algebra, what is the output of the natural join?
Các lựa chọn
AResult: (ID, NAME, COURSE)
| ID | NAME | COURSE |
|---|---|---|
| 1 | a | Math |
| 1 | a | Physical |
| 2 | b | Math |
BResult: (ID, NAME, COURSE)
| ID | NAME | COURSE |
|---|---|---|
| 1 | a | Math |
| 1 | a | Physical |
CResult: (ID, NAME, COURSE)
| ID | NAME | COURSE |
|---|---|---|
| 2 | b | Math |
DResult: (Student.ID, NAME, Enroll.ID, COURSE)
| Student.ID | NAME | Enroll.ID | COURSE |
|---|---|---|---|
| 1 | a | 1 | Math |
| 1 | a | 1 | Physical |
| 2 | b | 2 | Math |