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Announcements

Assignment 1

  • Described here.
  • Accounts for 10% of course grade.
  • Due Feb. 13.
  • Two parts:
    1. Implement Relational Algebra (today's subject).
    2. Use Relational Algebra to implement queries.
  • Questions? Let's discuss on Piazza.

Questions from last time

Thorough answers require more time than we have in class.

To be discussed on Piazza (not there yet):

  1. How can you use a UUID as a primary key if there is even the tiniest chance that it won't really be unique?

  2. Do foreign keys have "back-pointers"?

  3. How do you create a loop of foreign keys, e.g. from A to B and from B to A?

Reading for today

  • R & G, chapter 4, sections 1 and 2.
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