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HAP 709: Healthcare
Databases
Introduction to Database Structures
By Farrokh Alemi, Ph.D.
Francesco Loaiza, Ph.D. J.D.
Updated by Janusz Wojtusiak, Ph.D.
Fall 2008
What is database?
• Is an Excel table with students’ grades a
database?
• Is your notebook a database?
• Is a phonebook a database?
• Is the GMU schedule of classes a
database?
• Is a medical record of a patient a
database?
• Is a list of nurses working in a hospital a
database?
What is database?
• Database is a collection of data with
defined structure and purpose.
• Wikipedia: A Database is a structured
collection of data which is managed to
meet the needs of a community of users.
• Wordnet: Database is an organized body
of related information.
What is computer database?
• Computer database is a database stored
in a computer.
• It is usually managed by special software
called Database Management System
(DBMS).
• There are many DBMS systems available
– Access, Oracle, MUMPS, dBASE, portgress,
sql server, mysql, db2, …
Objectives of this lecture
• Learn about flat, hierarchical, relational,
and object-oriented databases
• Learn about information-less databases
If checking an information item
takes a fraction of a second, why
is it that we can go through billions
of information items in a fraction
of a second?
Types of Data Structures
•
•
•
•
Flat data
Hierarchical data
Relational data
Object-oriented data
Flat Models
Student
ID
Name
4561
Ali Safaie
7878
Mike
Smith
8954
Mike
Smith Jr.
Midterm
grade
B
C
A
Final
grade
Address
Zip code
...
A
1311
Manor
Park
22101
...
B
1619
Ozkan
Street
44115
...
C
2121
Euclid
563
22101
...
Flat Data
Advantages
• Most software include free access to flat data
files. For a small number of cases, flat
databases do a reasonably fast job.
• Most analytical software use flat data.
Disadvantages
• Flat databases waste computer storage by
requiring it to keep information on items that
logically cannot be available.
• Flat databases are not conducive to complicated
search queries
Relational Databases
In a relational data base, one
stores a record with related fields
as data.
In a relational database, tables do
not need to be of the same size
Example
Table for "Students grades"
Student ID
Name
Mid-term
Final
4561
Ali Ghadiri
B
A
7878
Mike Smith
C
B
8954
Mike Smith Jr.
A
C
Key column
Table for "Students' contact information"
Student ID
Address
Zip
8954
2121 Euclid 563
22101
4561
1311 Manor Park
22101
7878
1619 Ozkan Street
44115
Key column
Advantages of Relational
Databases
• Data can be examined from many different
perspectives.
• No need to enter missing information for
variables that are not logically possible.
• Easy to modify because adding new
concepts involves adding new Tables, not
altering old ones.
Hierarchical models
Data models in which the
relationship between higher and
lower items are inherited.
Example of Hierarchal Model
• File items on your desk top
Advantages of Hierarchical Models
Advantages
• Operations on parents save time and
affect all children.
Disadvantages
• Many relationships are not hierarchical
Object-oriented data models
Data are organized in the form of “objects”
that represent real world entities. Each
objects have its properties, that can be
regular values or other objects.
Advantages of Object-oriented
models
Advantages
• High efficiency
• Use of the actual “real life” entities as
objects
• Integration with object-oriented
programming languages (C++, Java, C# …)
Disadvantages
• Lack of one good standard
Distributed data models
Data are kept in different settings and on
different computers. Distributed databases
need not only addresses for where the data
are but also need an audit trail
Example of Distributed
Database
World Wide Web
Advantages of Distributed
Databases
• Security of these databases are difficult to
maintain.
• Many agreements must be made ahead of
time.
• Data loss is limited to nodes affected.
• Decentralized databases are more flexible
and allow different units to update and
maintain their own data.
• Variation in quality of data
Data-less Information
Systems
Distributed Databases without
data until need arises, less
problems with privacy of patients
Components of a Data-less
System
• Decoder
• Communicator
• Analysis
Advantages of the Data-less
Information Systems
• The system is substantially less expensive than
centralized registries as it requires no new
equipment and little personnel.
• The use of the system does not require vague
and time-independent patients’ consents.
• The system does not require duplication of data
in different databases.
Inductive Databases
Researchers investigate
databases that can answer
questions about things which are
not in that databases. They use
artificial intelligence to give
“plausible” answers.
Take Home Lesson
Structure makes it possible to
process and analyze large amount
of data