Refining an ER Diagram

• 1st diagram translated: Workers(S,N,L,D,S) Departments(D,M,B)

  • Lots associated with workers.

• Suppose all workers in a dept are assigned the same lot: D L

• Redundancy; fixed by: Workers2(S,N,D,S) Dept_Lots(D,L)

• Can fine-tune this: Workers2(S,N,D,S) Departments(D,M,B,L)

Before:

After:

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