Download Fundamentals of Database Design

Fundamentals of
Database Design
John Villamil-Casanova
Executive Vice President & CIO
The Aspira Association
202.835.3600 ext. 123
[email protected]
Agenda
Introduction and participants needs
We will review “what is a database;”
Understand the difference between data
and information;
What is the purpose of a database system;
How to select a database system;
Database definitions and fundamental
building blocks;
Agenda (2)
Database development: the first steps;
Quality control issues;
Data entry considerations;
What is a database
A database is any organized collection of
data. Some examples of databases you
may encounter in your daily life are:
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a telephone book
T.V. Guide
airline reservation system
motor vehicle registration records
papers in your filing cabinet
files on your computer hard drive.
Data vs. information:
What is the difference?
What is data?
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Data can be defined in
many ways. Information
science defines data as
unprocessed information.
What is information?
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Information is data that
have been organized and
communicated in a
coherent and meaningful
manner.
Data is converted into
information, and
information is converted
into knowledge.
Knowledge; information
evaluated and organized
so that it can be used
purposefully.
Why do we need a database?
Keep records of our:
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Clients
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Staff
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Volunteers
To keep a record of activities
and interventions;
Keep sales records;
Develop reports;
Perform research
Longitudinal tracking
What is the ultimate purpose of
a database management
system?
Is to transform
Data
Information
Knowledge
Action
More about database definition
What is a database?
Quite simply, it’s an organized collection of data. A
database management system (DBMS) such as
Access, FileMaker, Lotus Notes, Oracle or SQL
Server which provides you with the software
tools you need to organize that data in a flexible
manner. It includes tools to add, modify or
delete data from the database, ask questions (or
queries) about the data stored in the database
and produce reports summarizing selected
contents.
Let’s explore some examples
Outlook contacts
Aspira Association MIS
KidTrax
GIS-GPS systems
Types of Databases
Non-relational databases
Non-relational databases place information in field categories that we create so
that information is available for sorting and disseminating the way we need it.
The data in a non-relational database, however, is limited to that program and
cannot be extracted and applied to a number of other software programs, or
other database files within a school or administrative system. The data
can only be "copied and pasted.“ Example: a spread sheet
Relational databases
In relational databases, fields can be used in a number of ways (and
can be of variable length), provided that they are linked in tables. It is
developed based on a database model that provides for logical
connections among files (known as tables) by including identifying
data from one table in another table
Selecting a Database
Management System
Database management systems (or DBMSs) can be divided into
two categories -- desktop databases and server databases.
Generally speaking, desktop databases are oriented toward
single-user applications and reside on standard personal
computers (hence the term desktop).
Server databases contain mechanisms to ensure the reliability
and consistency of data and are geared toward multi-user
applications.
Selecting a database system:
Need Analysis
The needs analysis process will be specific to your organization but, at
a minimum, should answer the following questions:
How many records we will warehouse and for how long?
Who will be using the database and what tasks will they perform?
How often will the data be modified? Who will make these
modifications?
Who will be providing IT support for the database?
What hardware is available? Is there a budget for purchasing
additional hardware?
Who will be responsible for maintaining the data?
Will data access be offered over the Internet? If so, what level of
access should be supported?
Some Definitions
A File: A group or collection of similar records, like INST6031 Fall
Student File, American History 1850-1866 file, Basic Food Group
Nutrition File
A record book: a "rolodex" of data records, like address lists,
inventory lists, classes or thematic units, or groupings of other
unique records that are combined into one list (found in AppleWorks,
FileMaker Pro software).
A field: one category of information, i.e., Name, Address, Semester
Grade, Academic topic
A record: one piece of data, i.e., one student's information, a recipe,
a test question
A layout: a design for a database that contains field names and
possibly graphics.
Database glossary
Fundamental building blocks
Tables comprise the fundamental building blocks of any database. If you're familiar with
spreadsheets, you'll find database tables extremely similar. Take a look at this example of a
table sample database:
The table above contains the employee information for our organization -- characteristics
like name, date of birth and title. Examine the construction of the table and you'll find that
each column of the table corresponds to a specific employee characteristic (or attribute in
database terms). Each row corresponds to one particular employee and contains his or her
information. That's all there is to it! If it helps, think of each one of these tables as a
spreadsheet-style listing of information.
Where do we start?
Let’s explore your “paper
system”
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Client intake forms
Job application form
Funders reports
Database modeling:
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Define required fields from
“forms” or required reports
Avoid repetition
Keep it simple
Identify a unique identifier
or primary key
Some Quality Control
Considerations
Remember “garbage in –
garbage out”. Some examples
and how to prevent this.
Quality management
encompasses three distinct
processes: quality planning,
quality control, and quality
improvement
Quality Planning in relation to
database systems design:
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Who will perform data
entry?
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Training? On-line help?
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How data entry will be
performed?
Data entry considerations
Define “must” enter fields – no record is complete
unless: such and such is entered;
Make data entry fool proof. Example: Grade level can
be entered as a number (8 or 8th or eight). By using a
pull-down menu with the correct data format these
mistakes can be avoided.
Data Entry – additional
considerations
Barcode scanners
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USB or
Wireless attached to a
Palm or Pocket PC
Pocket PC
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WiFi 802.11g,
Bluetooth
Wireless networks
(real-time on demand
systems)