Download Week 5

Lecture 5
MIS/Decision Support
Content for Weeks 5 and 6
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Discussion of OLTP v MIS/Decision Support
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Review characteristics of a Normalised Relational
Data Model
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Consider the suitability of relational model for
online transaction processing (OLTP); table access
example
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Consider the unsuitability of relational model for
informational processing; table access example
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Consider why organisations will generally
implement informational systems on a different
platform to the transaction processing systems
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Decision-making
As defined by Baker et al in their 2001 study
“efficient decision-making involves a series of
steps that require the input of information at
different stages of the process, as well as a
process for feedback”.
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Decision Making Process
Decision making at different levels
• Operational
• Tactical
• Strategic
Information and knowledge form the
backbone of the decision making process
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Types of Decision Making
Operational
• Related to daily activities with short-term effect
• Structured decisions taken by lower management
Tactical
• Semi-structured decisions taken by middle management
Strategic
• Long-term effect
• Unstructured decisions taken by top management
• Decision making steps include
• Problem identification
• Finding alternative solutions and making a choice
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DIKDA Cycle
User
Decision
Making
Triggering
To be used in
Applies
Intelligence to
Analysis
Knowledge
Forming
Data
CO6002 Modern Databases
To produce
Lecture 5
Action
Generating
more
Information
6
Decisions
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•
Made up of a composite of information,
data, facts and beliefs.
Data by itself does not constitute useful
information unless it is analysed and
processed.
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A Decision
• Is only as good as the data that informed it
• Is only as good as the system which exists
to implement it
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Is only good if you have the means to
implement it
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Is only good if other people understand it
and are agree/ready to implement it
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Operational vs. Informational
Processing
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OLTP and OLAP
OLTP
• On-line Transaction Processing
• Concerned with day to day running of the
business
OLAP
• On-line Analytical Processing
• Analysis of large amounts of data for
management decision-making purposes
• Often historical and multi-site
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OLTP vs. OLAP (MIS Decision
Support)
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On-line Transaction Processing
(OLTP)
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•
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Relational databases are optimized for OLTP and are
designed to meet the day-to-day operational needs of
the business.
OLTP systems tend to organize data around specific
processes, such as order entry. Performance is tuned for
those operational needs by using a normalized data
model which stores data by using database normalization
rules. Consequently, the database can retrieve a small
number of records very quickly.
Attempting to use a database that is designed for OLTP
as a data warehouse will result in a very slow query
performance making it difficult to perform analysis on the
data.
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OLAP or Decision Support
System (DSS) Processing
In a data warehousing environment, the relational
databases need to be optimized for data retrieval and
tuned to support the analysis of business trends and
projections.
This type of informational processing is known as online
analytical processing (OLAP) or decision support system
(DSS) processing. OLAP is also the term that database
designers use to describe a dimensional approach to
informational processing.
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OLAP Characteristics
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A dimensional database needs to be designed to support
queries that retrieve a large number of records and that
summarize data in different ways. A dimensional
database tends to be subject oriented and aims to
answer questions such as, “What products are selling
well?” “At what time of year do certain products sell
best?” “In what regions are sales weakest?”
In a dimensional data model, the data is represented as
either facts or dimensions. A fact is typically numeric
piece of data about a transaction, such as the number of
items ordered. A dimension is the reference information
about the numeric facts, such as the name of the
customer. Any new data that you load into the
dimensional database is usually updated in a batch, often
from multiple sources.
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