Today, another language for talking about databases. This one is the Tuple Relational Calculus for writing queries that describe information to be extracted from the linked tables of a relational database. There’s a separation of roles here: the tuple relational calculus is good for succinctly stating what we want to find out; while relational algebra from the last lecture describes how to combine and sift tables to extract that information from the data. We distinguish what information we want from how to compute it.
There were also announcements about the CompSoc bowling trip, and the Equalise week of events raising funds for the Edinburgh Rape Crisis Centre.
Link: Slides for Lecture 6; Recording
Homework
1. Read This
Either or both of these study guides.
- Study Skill Essentials: Note Taking. The University of Manchester.
- How to Take Lecture Notes. wikiHow.
Both are good, but only wikiHow has those pictures.
2. Do This
Work through the exercises for Tutorial 2: Relational Modelling. For more practice, try some of the additional examples.
References
A timeline of Facebook Graph Search.
describe
From 2013 …
- Sign up for Facebook Graph Search
- How to Use Facebook’s Graph Search to Supercharge Your Professional Network
- How to Use Facebook’s Graph Search to Improve Your Marketing
- 17 Ways Marketers Can Leverage Facebook Graph Search
- Why Graph Search Could Be Facebook’s Largest Privacy Invasion Ever
… to 2016
More search, less graph.
Some of those examples:
- Photos tagging Facebook user #4
- Restaurants visited by Mark Zuckerberg
- People who live in Bogota who have visited Fiji
Build your own with http://graph.tips
How it’s Done
Read the technical paper by the computer scientists who built this:
Unicorn: A System for Searching the Social Graph
Presented at the 39th International Conference on Very Large Data Bases, VLDB 2013
“Unicorn is designed to answer billions of queries per day at latencies in the hundreds of milliseconds…”
Equalise Film Screening
