Information structures and implications 2015 Prof Bettina Berendt

Information structures and implications 2015 Prof. Bettina Berendt Thanh Le Van 22 September 2015

Most important URL for this course http: //people. cs. kuleuven. be/~bettina. berendt/teaching/2015 -16 -1 stsemester/isi/ 2

Today Who are we? Course overview and practical things What are data? What is a database? What does this mean for you? Some relevant concepts Introducing our first case study 3

Course overview and practical things

Lectures 5

Exercise sessions Start in week 3 Are an integral part of the course Hands-on experience with data(bases) Detailed plan will follow Direct preparation for the assignments 6

Assignments and evaluation Proceed from “exercise-style” to “mini-project” Written and oral (presentation of your results) Are the main basis of evaluation Plus participation in class No exam No second examination chance in September! 7

Materials Plus extras: online or distributed otherwise 8

Ask questions! In the lecture In the exercise session In the Toledo forum 9

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Today Who are we? Course overview and practical things What are data? What is a database? What does this mean for you? Some relevant concepts Introducing our first case study 11

. . . and now for the interactive part

(Just a reminder of what we did) 1. Introduce your neighbour in terms of data 2. “How else can you describe a person? “ – datafying ourselves 3. Do you use databases? Which ones? How? 4. Other people have similar experiences. . . “Homebrew Databases“ – Amy Voida, Ellie Harmon, and Ban Al-Ani. 2011. Homebrew databases: complexities of everyday information management in nonprofit organizations. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (CHI '11). ACM, New York, NY, USA, 915 -924. – Paper: http: //ellieharmon. com/docs/Voida. Harmon. Al. Ani-Homebrew-CHI 2011. pdf – Talk: http: //people. csail. mit. edu/karger/Talks/Homebrew. Databases. pdf 13

[…] it is on account of the grown-ups and their ways. When you tell them that you have made a new friend, they never ask you any questions about essential matters. They never say to you, "What does his voice sound like? What games does he love best? Does he collect butterflies? " Instead, they demand: "How old is he? How many brothers has he? How much does he weigh? How much money does his father make? " Only from these figures do they think they have learned anything about him. If you were to say to the grown-ups: "I saw a beautiful house made of rosy brick, with geraniums in the windows and doves on the roof, " they would not be able to get any idea of that house at all. You would have to say to them: "I saw a house that cost $20, 000. " Then they would exclaim: "Oh, what a pretty house that is!" 14

Today Who are we? Course overview and practical things What are data? What is a database? What does this mean for you? Some relevant concepts Introducing our first case study 15

Some relevant concepts

Databases vs. files Files – – Each program defines structure Several programs: redundancies, or need for transformation Databases – – Data + metadata* that describe the structure Independent of programs * At least in traditional databases 17

An example: What should the KU Leuven student database contain? 18

Tables, also known as relations, referring to one another Relational databases 19

An example of metadata of such a database 20

Goals? – – – Structure Make accessible manipulate Hold consistent Store “securely” data 21

Database A set of centrally managed, permanently stored data, which always have to be available to different applications • • • All data that are relevant for all previewed applications Every application sees/access only relevant data Different applications share the same data 22

Some definitions Database system – – Database (the data themselves) Database management system (DBMS) DBMS – – – Create database structure (“schema”) Add, delete, modify data Access / query data 23

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A foretaste … ER 25

Fname Minit Lname Salary Name Sex Number N WORKS_FOR Name 1 Locations Address Ssn Start. Date EMPLOYEE 1 1 Bdate DEPARTMENT 1 MANAGES supervisor 1 N N 1 WORKS_ON SUPERVISES CONTROLS Hours supervisee M HAS_DEP. N PROJECT N Name DEPENDENT Location Number Name Sex Birth. Date Relationship

A foretaste … SQL SELECT DISTINCT Pnumber FROM PROJECT WHERE Pnumber IN (SELECT Pnumber FROM PROJECT, DEPARTMENT, EMPLOYEE WHERE Dnum=Dnumber AND …) OR Pnumber IN (SELECT Pnumber FROM … WHERE …) ; 27

Today Who are we? Course overview and practical things What are data? What is a database? What does this mean for you? Some relevant concepts Introducing our first case study 28

Exercise for next session 1. Read the European Parliament texts that are hyperlinked on the course page 2. Think of a (small) research question you could have from the perspective of your discipline – or another one 3. Model the data that you would need to answer it with “boxes, bubbles and diamonds” 29

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