Here is a table for classes at a college, with numbered time periods in each day

Question

Here is a table for classes at a college, with numbered time periods in each day:

Name

Department

Room

Period

Java 1

CS

100

5

Java 2

CS

110

4

Data Structures

CS

100

6

Calc 1

Math

350

6

Calc 2

Math

390

6

Linear Algebra

Math

350

4

a.Find a functional dependency (FD) with one attribute (other than Name) on each side that holds for this instance.

b. Disprove the proposed FD “department period -> room”

c. Find a single-column key and a multi-column key that hold for this instance

d.Propose a decomposition that removes the redundancy implied by the FD you found in a. Show the smaller table in full and state what column can be dropped in the larger table compared to the original table.

Name

Department

Room

Period

Java 1

CS

100

5

Java 2

CS

110

4

Data Structures

CS

100

6

Calc 1

Math

350

6

Calc 2

Math

390

6

Linear Algebra

Math

350

4

Explanation / Answer

a. Room -> Department

b. For department Math and period 6, room can be either 350 or 390. Hence this FD is disproved

c. Single column key - Name (Name determines department, period and room). Multi column key is (Period, room)

d. Decomposition will be (room, department) and (Name, room, Period)

Table 1:

CS 100

CS 110

Math 350

Math 390

-----------------------------------------------------

Table 2:

Java 1

100

5

Java 2

110

4

Data Structures

100

6

Calc 1

350

6

Calc 2

390

6

Linear Algebra

350

4

Java 1

100

5

Java 2

110

4

Data Structures

100

6

Calc 1

350

6

Calc 2

390

6

Linear Algebra

350

4

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