Organizing Data and
Information
What is Data??
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Numbers, characters, images, or other method of recording,
in a form which can be assessed by a human or (especially)
input into a computer, stored and processed there, or
transmitted on some digital channel.
Data on its own has no meaning, only when interpreted by some
kind of data processing system does it take on meaning and
become information.
People or computers can find patterns in data to perceive
information, and information can be used to enhance
knowledge. Since knowledge is prerequisite to wisdom, we
always want more data and information.
What is Data??
Database Concepts
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Data
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is a valuable resource
collection of facts/figures/observations
storing, organizing, retrieving, sorting,
maintaining data are important activities.
to organize data you must understand:
Some Key Terminology
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FIELDS:
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Field Names: Each field is given a name
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A field is a single attribute of an entity
Entity can be person, place, object, event, idea
Examples: Name, Age, Salary
Field Value:
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Specific value/content of a field name
Ex.: “Joe Blow”, 30, 23000
Some Key Terminology
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RECORDS:
Group of related field values belonging to a given
entity under consideration
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FILE:
Group of related records
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DATABASE:
Group of related files
Section 035
Fields:
TCU ID
106-501-303
106-407-964
106-430-298
106-379-381
106-373-583
106-387-806
106-353-873
106-360-584
106-414-752
Preferred
Josie
Chris
Michael
Christopher
Katie
Cole
James
Emery
Hilary
Records
Field Names:
Last
Benor
Bosillo
Buono
Byars
Clement
Davis
Day
Dodson
Felton
Field Value:
Full Name
Benor,Josie Leiser
Bosillo,Christopher Wayne
Buono,Michael Vincent
Byars,Christopher R.
Clement,Katie R.
Davis,Cole St.Clair
Day,James Curtis
Dodson,Emery Anne
Felton,Hilary Schrader
Grd Basis
GRD
GRD
GRD
GRD
GRD
GRD
GRD
GRD
GRD
Status Units
Enrolled
3
Enrolled
3
Enrolled
3
Enrolled
3
Enrolled
3
Enrolled
3
Enrolled
3
Enrolled
3
Dropped
3
Data Hierarchy
Database
File
Record
Field
Character
Bits (0 or 1)
Data Hierarchy
Data Management
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Concerned with
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Data accuracy
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Security
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reliable source of data
reliable data entry
timeliness.
protecting data to keep it from being misused or lost
(authorized access, backup)
Data maintenance
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procedures used to keep data current (adding,
changing, deleting)
The Traditional Approach To Data
Management
Limitations of Files
 Data Redundancy – duplicate fields in multiple files
 Data Inconsistency – identical fields have different data
 Data Isolation – inaccessibility of data from other applications
 Security – nonexistent
 Data Integrity – accuracy of data in records
Database
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A Database - an organized collection of
related data that can service many
applications at the same time.
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A collection of data is not per se a database.
Organized means that you can easily find what
you want.
Related means that the data have significance
when viewed together.
Data Entities and Attributes
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Entity
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Generalized class of people, places, or things for
which data is collected, stored, and maintained
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Examples of entities include employees, customers, and
inventory
Attributes
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A characteristic of an entity
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For example, employee number, last name, first name,
hire date, and department number are attributes for an
employee
Keys
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Key:
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A field or set of fields in a record that is
used to identify the record
Primary Key
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A field or set of fields that uniquely
identifies the record
Keys and Attributes
The Database Approach to Data
Management
Advantages of Database
Approach
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Improved strategic use
of corporate data
Reduced data
redundancy
Improved data integrity
Easier modification and
updating
Data and program
independence
Better access to data
and information
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Standardization of data
access
Framework for program
development
Better overall protection
of the data
Shared data and
information resources
Disadvantages of Database
Approach
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Relatively high cost of purchasing and
operating a DBMS in a mainframe operating
environment
Increased cost of specialized staff
Increased vulnerability
Database Models
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Hierarchical (tree)
Network
Relational
Hierarchical Database Model
Network Database Model
Relational Database Model
A Relational Database Model
Link via a common field between tables
Relational database and keys
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A relational database is a collection of tables
that are related to one another based on a
common field.
A field, or a collection of fields, is designated
as the primary key.
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The primary key uniquely identifies a record in the
table.
When the primary key of one table is
represented in a second table to form a
relationship, it is called a foreign key.
Relating tables using a common
field
The primary key in the
Employer table (EmployerID) is
the common field that relates
this table to the Position table.
PositionID is the primary key in
the Position table. The EmployerID
field is a foreign key in this table.
Primary keys can only have one
occurrence in a table. Foreign keys
may have multiple occurrences.
Linking Database Tables
to Answer an Inquiry