Download Databases course of 2017-03-02

Databases
Dr. Ben Schroyen
Prof. dr. Marc Nyssen
Prof. dr. Frederik Questier
Vrije Universiteit Brussel
What's a database?
Who uses it?
For what?
How?
Filing cabinet
with files and records
database versus database system
A database consists of
an organized collection of data
for one or more uses,
typically in digital form.
A database system is a system intended to
organize
store
and retrieve
large amounts of data easily.
Example database
Patients
Patient
Telephone number
Charles Babbage
+52 487 987 673 109
Ada Lovelace
+52 477 879 999 678
John von Neumann
+1 3456 792 805 805
Konrad Suze
+49 278 999 777 010
Mitch Kapor
+1 0101 010 101 010
Vinton Cerf
+1 2379 994 783 111
Tim Berners-Lee
+49 234 824 601 346
John Quartermann
+1 4567 222 444 666
Robert Cailliau
+32 488 234 456 678
Better example
Patient
First name
Telephone number
Babbage
Charles
+52 487 987 673 109
Lovelace
Ada
+52 477 879 999 678
von Neumann
John
+1 3456 792 805 805
Suze
Konrad
+49 278 999 777 010
Kapor
Mitch
+1 0101 010 101 010
Cerf
Vinton
+1 2379 994 783 111
Berners-Lee
Tim
+49 234 824 601 346
Quarterman
John
+1 4567 222 444 666
Cailliau
Robert
+32 488 234 456 678
How to store
the data base?
How to store?
In Flat Text files?

Example: ict-contact-list.txt (1 ”record” per line)
Babbage#Charles#M#Prof. Dr.#Lovelace Castle##ICT dept.#Sussex#England
Suze#Konrad#M#Dr.#Neustrasse#2##Giessen#Deutschland

Disadvantages
– File corruption risk if computer fails while updating a file.
– Custom scripts necessary
– What if many people at the same time want to update the
data?
– No security features
How to store?
In a spreadsheet?
How to store? DBMS!
DataBase Management System
➢
➢
➢
➢
a software package that helps the use of integrated
collection of data records and files known as databases.
a set of computer programs that controls the creation,
maintenance, and the use of a database.
allows organizations to place control of database
development in the hands of database administrators
(DBAs) and other specialists.
allows different user application programs to easily
access the same database
ACID Rules
➢
Atomicity:
Either all the data changes in a transaction must happen, or none of them.
The transaction must be completed, or else it must be undone (rolled back).
➢
Consistency:
Every transaction must preserve the declared consistency rules for the
database.
➢
Isolation:
Two concurrent transactions cannot interfere with one another.
Intermediate results within one transaction must remain invisible to other
transactions.
➢
Durability:
Completed transactions cannot be aborted later or their results discarded.
They must persist through (for instance) DBMS restarts.
ACID Rules
Atomicity
In a transaction involving
two or more updates,
– either all of the updates
are committed
– or none are (roll back).
The DBMS helps with the

Construction of the structure
– but does not provide a good database model or scheme

The data storage

Access mechanisms
– Network access

Security
Own responsability?

Logging

Backup

Replication
DBMS examples?
DBMS examples
➢
Free Open Source Software
➢
Non-free, closed source Software
Relational DBMS
Data Organization Hierarchy
Records and fields
in a single file or table
Relational model
Concept: scheme
First name
name
Tel.nr
patient
Relational model
Concept: scheme
COLUMN IN TABLE
Name
First name
Tel.nr
patient
TABLE
Relational model

Unique key needed!
Name
FirstName TelNr
StateNumber
Babbage
Charles
+52 487 987 673 109 A2367995511
Lovelace
Ada
+52 477 879 999 678 B2537956789
von Neumann John
+1 3456 792 805 805 A1234567890
Suze
Konrad
+49 278 999 777 010 A9876543210
Kapor
Mitch
+1 0101 010 101 010 A5647382910
Cerf
Vinton
+1 2379 994 783 111
Berners-Lee
Tim
+49 234 824 601 346 A2356842351
Quarterman
John
+1 4567 222 444 666 A5208525577
Cailliau
Robert
+32 488 234 456 678 A4810103578
A4538813932
Relational model

table doctors
FirstName
Name
DoctorNumber
Louis
Pasteur
123-456-789
Albert
Schweitzer
456-789-012
Gregory
House
789-123-456
Anne
No
234-234-234
Andreas
Vesalius
888-999-000
Relational model
doctor
is doctor of
patient
Relational model
is doctor of
Doctor number
State number
888-999-000
B2537956789
789-123-456
A2356842351
234-234-234
A4538813932
456-789-012
A5647382910
456-789-012
A4810103578
Relational model
Entity–relationship model
StateNumber
DoctorNumber
doctors
Name
FirstName
Is doctor of
TelNr
patients
Name
FirstName
Name and StateNumber
of Patients born in 1950?
Name
FirstName
StateNumber
BirthYear
Babbage
Charles
A2367995511
1791
Lovelace
Ada
B2537956789
1815
von Neumann
John
A1234567890
1903
Suse
Konrad
A9876543210
1910
Kapor
Mitch
A5647382910
1950
Cerf
Vinton
A4538813932
1943
Berners-Lee
Tim
A2356842351
1955
Quarterman
John
A5208525577
1954
Cailliau
Robert
A4810103578
1947
Structured Query Language
SQL
Structured Query Language
SQL
Basic Query :

SELECT list of table columns/fields in the result (or * for all)

FROM

WHERE (optional) the conditions about the tables
list of tables to be queried
and/or the relations between the tables
Name and StateNumber
of Patients born in 1950?
Sql query:
SELECT patients.Name, patients.StateNumber
FROM patients
WHERE patients.BirthYear = 1950
Name
StateNumber
Kapor
A5647382910
Name and StateNumber
of Patients born between
1940 and 1950?
Sql query:
SELECT patients.Name, patients.StateNumber
FROM patients
WHERE patients.BirthYear > 1940
AND patients.BirthYear < 1950
What are the Name and the StateNumber
of the patients of Doctor Schweitzer?
Patients
Doctors
Name
FirstName
TelNr
StateNumber
First
Name
Name
DoctorNumber
Babbage
Charles
+52 487 987 673 109
A2367995511
Louis
Pasteur
123-456-789
Lovelace
Ada
+52 477 879 999 678
B2537956789
Albert
Schweitzer
456-789-012
von Neumann
John
+1 3456 792 805 805
A1234567890
Gregory
House
789-123-456
Suze
Konrad
+49 278 999 777 010
A9876543210
Anne
No
234-234-234
Kapor
Mitch
+1 0101 010 101 010
A5647382910
Andreas
Vesalius
888-999-000
Cerf
Vinton
+1 2379 994 783 111
A4538813932
Berners-Lee
Tim
+49 234 824 601 346
Quarterman
John
Cailliau
Robert
DoctorNumber
StateNumber
A2356842351
888-999-000
B2537956789
+1 4567 222 444 666
A5208525577
789-123-456
A2356842351
+32 488 234 456 678
A4810103578
234-234-234
A4538813932
456-789-012
A5647382910
456-789-012
A4810103578
Relations
What are the Name and the StateNumber
of the patients of Doctor Schweitzer?
SELECT Patients.Name, Patients.StateNumber
FROM Patients, Doctors, Relations
WHERE Doctors.Name = 'Schweitzer'
AND Doctors.DoctorNumber = Relations.DoctorNumber
AND Patients.StateNumber = Relations.Statenumber
Name
StateNumber
Kapor
A5647382910
Calliau
A4810103578
Excercise 1: SQL online
See http://www.w3schools.com/sql/
Explore the examples of the following pages:
●
Intro
●
Syntax
●
SELECT
●
WHERE
●
AND
●
LIKE
●
Wildcards
and construct a query for:
●
Show all customer names from Paris
●
Show all customer names starting with m
For each example:
click on “Try it yourself”
Click on 'Run SQL'
Check the results for the query
Change a similar query for our exercise
phpMyAdmin: an easy general way
to access data bases
Mysql
database
Internet
Apache webserver
phpMyAdmin
phpMyAdmin
phpMyAdmin
phpMyAdmin
Excercise 2: phpMyAdmin demo
Optional
Or alternative if you cannot login for excercise 3
Explore this demo:
http://demo.phpmyadmin.net/
– “Latest phpMyAdmin stable release; direct login”
– Explore, databases, tables, sql queries, searches, ...
Exercise 3: SQL in phpMyAdmin
Step 0: Activate VUBnetID : https://www.vub.ac.be/tools/pam
Step 1: Register database user: https://minf.vub.ac.be/john/mysql
Step 2: Login at https://minf.vub.ac.be/MyAdmin/
Everyone has access to the 'student' database and 3 tables:
– patients
– doctors
– <vubnetid>_medrec
Construct a query for the name and address of the patients of
doctor Medderie
Excercise 4
Design a medical record table
Modify the table vubnetid_medrec by changing the 3
initial fields and adding new relevant fields.
Choose the field types (varchar, date, …) wisely.
Design a relational database scheme.
Maybe initially on paper, but finally digital, e.g. in
LibreOffice Draw.
Exercise 5: optional
database driven websites
Create webpages based on database queries
Extend your website (course 2) with a standalone
webpage that displays the query of the previous
excercise.
PHP templates in
minf.vub.ac.be:/pcrw/WD-INF/VB_WEB/
References and sources

Een introductie tot gegevensbanken, Kris Luyten,
Tom Van Laerhoven, Expertisecentrum Digitale
Media, Limburgs Universitair Centrum,
Wetenschapsdagen 2002
http://bisi.vub.ac.be/minf/docs/db-Luyten-Van-Laerhoven.pdf


Database systems, the complete book, HectorGarcia Molina, Jeffrey D. Ullman, Jennifer Widom,
Prentice Hall 2002, ISBN 0-13-031995-3
Invitation to Computer Science, International
Edition, 5th Edition (2009), by G. Michael
Schneider, Judith L. Gersting, Course Technology,
Cengage Learning