Database Design and Management

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Lecture 6

• Database Design and Management
• Peter Flett

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Recap why?

• Data
• The raw facts or observations that are
  considered to have little or no value until they
  have been processed and transformed into
  information

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Data

• A series of non-random symbols,
• numbers, values or words.
• A series of facts obtained by observation or
  research.
• A collection of non-random facts.
• The record of an event or fact.

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Types of Data

• Formatted
• Free text
• Images
• Audio
• Video
• Models
• Hard and Soft data

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Information

1. Data that has been processed so that they are
   meaningful
2. Data that has been processed for a purpose
3. Data that has been interpreted and understood by
   the recipient
4. Information acts to reduce uncertainty (risk)
   about a situation or event

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Examples of information

• A bank statement
• A sales forecast
• A telephone directory
• Management report
• Financial report
• MISs, DSSs, ESs, and ERP systems

Beware of paralysis by analysis
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Capturing Data

• Many sources
• Can often be problematic
• Open to interpretation
• E.g. different types of research methodology
• Spin doctoring
• Lying with statistics

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Inputting Data

• Inputting of data is tedious.
• Hardware can help
• Scanning information (still requires a degree of
  data entry

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Creating Information Data Process

• A process used to convert data into information.
• Examples include sorting, searching, filtering,
  summarising, classifying, calculating and
  combining

Transformation Process (the data process)
Data
Information
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Knowledge

• An accumulation of information, building on
  existing ideas and experience
• This should be the result of information

Q. How does an organization retain knowledge?
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Relating data, information and knowledge
Learn Interpret
Outcomes
Enhanced/Increased Knowledge
Decisions/Actions
A cyclical improvement process?
Understand Interpret Decide Act upon
Data
Information
Converts
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Perspectives on Information

• Informative
• Type of information what it tells us
• Nature of form
• How is the information presented
• Time interval
• When is the information communicated to us
• Scope
• The part of the org to which the info relates

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Value of Information

• Tangible value
• A value or benefit that can be measured directly,
  usually in monetary terms
• Value of information minus cost of gathering
  information

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Value of Information

• Intangible value
• A value or benefit that is difficult or
  impossible to quantify
• E.g. Improvement in decision behaviour minus cost
  of gathering information

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Sources of Information

• Formal communication
• reports, accounting statement, programs, memos
  etc.
• Informal communication
• Conversation, notes etc.

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Information Quality
Time Content Form Additional Characteristics Additional Characteristics
Timeliness Accuracy Clarity Clarity Confidence in source
Currency Relevance Detail Detail Reliability
Frequency Completeness Order Order Appropriate
Time Period Conciseness Presentation Presentation Received by correct person
Scope Media Media Sent by correct channels
OBrien (1993)
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Summary

• Information can be derived from data in many
  different ways
• Gathering and processing data costs money
• Organizations use a wide variety of information
  for different purposes
• The characteristics of that information have a
  major impact on organizational effectiveness

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The Design Process

• Crucial, good design prevents,
• Redundant data
• Inconsistent data
• Inflexibility of use
• Limited sharing of data
• Limited security

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For example
Student Reg No Course Fee
12345 ISM 4000
12346 MBA 3500
12347 BUS 4200
12348 ISM 4000
12349 MBA 3500
Redundancy -course fee repeated
Deletion - if student 12347 withdrew from course
we would loose BUS fee information
Updating - If MBA fee changed we would have to
alter records of all MSC students
Insertion - A new course cannot be added until
a student registers
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5 steps to database design ( Dowling)

• What is the purpose of the database?
• SMART Specfic, Measurable, Achievable, Relevant,
  Time related
• Determine the information requirements of the
  database

( these stages are all key parts of the system
analysis that has to take place prior to
implementation )
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5 steps to database design ( Dowling)

• Produce a logical model of the information
  requirements (E-R model) SSADM
• Convert the logical data model to a physical data
  model
• I.e. go from the conceptual world to the real
  world
• From the E-R model to the Relational Model
  (normalisation)
• Implement the physical design