Transcript Bounded Rationality

Welcome
05G11389
Management Information Systems
Session 2
Data Bases
Who uses them??
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Banks
Airlines
Business
Libraries
Governments, FBI, CIA, Interpol
Artisists, film makers
Scientists, DNA sequences…
Astronomers…Chemeists…
Who does not?
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 8-12 billion USD annual
 IBM, Oracle, Informix, Sybase, NCR,
Microsoft, MySQL,…
History
 1890 US Census asked Herman Hollerith to
develop punch card machine.
 Hollerith founded company, merged with
another firm which became IBM.
 Computer development fuelled by military
in WW1, to track logistics and production of
weapons. WWII, advanced optimization and
cryptography
 1960 US DOD commissions COBOL
(Common business oriented language)
 Codasyl (US Gov) and IMS (IBM and NASA)
History
 "A Relational Model of Data for Large
Shared Data Banks," Edgar F. (Ted)
Codd Communications of the ACM
1970.
 Data independence from hardware
 High level procedural language to
manipulate data
 IBM had IMS
 System R (SQL)
 Ingres (US Military, UC Berkeley)
History
 Ingres & System R employees
circulate through Silicon valley circles
 1980 IBM SQL/DS hits market
 Codd awarded ACM Turing Award
 1980s - Oracle marketing
demonstrates superiority of relational
model
Terminology
 Data sources
 Database: persistent collection of data
 Database Management System (DBMS):
software that controls access to the database
 Database Administrator (DBA): person who
controls database
 Data Model: general structure of the data in
the database
 Data Language: commands used to define
the data model and give users access to the
database; SQL (Structured Query Language)
Normal Forms
 Non-normalized data
 1NF
 no repeating fields or groups of fields
 all values in field are “atomic”
 2NF
 Already in 1NF
 Each non-key field is FD on entire primary key
 3NF
 Already in 2NF
 no non-key element is FD on any non-key
element
Normal forms inclusive
ONF2
1NF
2NF
3NF
BCNF
4NF
5NF
Up 270+ Normal forms in Lit – Academic
abstractions
To 1NF
users
name
company
company_address
url1
url2
Joe
ABC
1 Work Lane
abc.com
xyz.com
Jill
XYZ
1 Job Street
abc.com
xyz.com
What if some companies have 3 URLS? 4, 5, …N?
1st Normal Form
users
userId
name
company
company_address
url
1
Joe
ABC
1 Work Lane
abc.com
1
Joe
ABC
1 Work Lane
xyz.com
2
Jill
XYZ
1 Job Street
abc.com
2
Jill
XYZ
1 Job Street
xyz.com
We have solved the URL problem,
But created another….
Eliminate horizontal redundancies
2nd Normal Form
Primary Key
users
userId
name
company
company_address
1
Joe
ABC
1 Work Lane
2
Jill
XYZ
1 Job Street
urls
Foreign Key
urlId
relUserId
url
1
1
abc.com
2
1
xyz.com
3
2
abc.com
4
2
xyz.com
Eliminate vertical redundancies
3rd Normal Form
users
userId
name
relCompId
1
Joe
1
2
Jill
2
companies
compId
company
company_address
1
ABC
1 Work Lane
2
XYZ
1 Job Street
urls
urlId
relUserId
url
1
1
abc.com
2
1
xyz.com
3
2
abc.com
4
2
xyz.com
All columns must relate directly to the primary key
Finding Balance
user
PK
user_id
FK1
first_name
last_name
nickname
unit
street_number
street_name
street_type
quadrant
web_url
picture
notes
postal_code
user_phone
PK,FK1
PK,FK2
postal_code
FK1
city_id
PK
phone_id
FK1
type_id
area_code
NXX
NCX
country_id
extension
email
postal_code
PK
user_id
phone_id
phone
PK
address
FK1
user_id
format
FK2
city
PK
city_id
FK1
name
province_id
PK
type_id
user_id
department_id
province_id
FK1
Name
Abbreviation
country_id
country_id
Name
phone_code
department
PK
department_id
FK1
name
company_id
province
PK
PK
type
user_department
PK,FK1
PK,FK2
country
type
company
PK
company_id
name
Open Source…
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www.opensource.org
Linux (OS)
Apache (Web Server)
MySQL (DB)
PhP (Scripting)
JBoss (Web Server)
Samba (file & content)
OpenOffice (Office Apps.)
Many more…
Open Source Pros..
 Cost. As far as software acquisition
costs go, open source products are free.
 Flexibility. Just like Linux, open source
software frees companies from vendor
lock-in.
 Close to the code. With open source,
enterprise users can pinpoint problems in
specific code and suggest patches to solve
problems.
 Growing support. Vendors such as HP,
Red Hat and Novell are enhancing support
for open source products beyond Linux.
Open Source Cons..
 Cost. While acquisition costs are free, corporate users
must pay for support and services, and there are often
costs associated with training IT staff.
 Integration. Today, users are on their own when it
comes to integrating open source products into legacy
infrastructure, although this is starting to change with
companies as varied as Gluecode and HP rolling out
support for open source stacks.
 Capabilities. Today’s open source databases and
application servers are technically very good, but still
not up to par with heavy-duty commercial offerings
such as DB2 or WebLogic.
 Intellectual property. The SCO Group’s legal assault
against Linux should serve as a warning shot for any
company considering open source. Understand the
open source license governing the product and what
your rights and responsibilities are.