Express the following queries in relational algebra.
a. (5.16)
b. (5.20)
c. (5.23)
a. ```
?Name(?DeptId='CS' OR DeptId= 'EE' (Professor))
```
b. ```
?Name(?CrsCode='CS305' AND CrsCode2= 'CS315' (BigJoin)
```
where BigJoin is de?ned as:
```
Student Id=StudId Transcript Transcript[StudId,CrsCode2,S2,G2]
```
Observe that a careful renaming of the attributes has allowed us to use the natural join between the two occurrences of Transcript and to make the expression shorter.
c. ```
?Id(Student) ? ?StudId(Transcript)
```
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