Chapter 4
Operations and Transactions
The Strategic
Management of
Information
Systems
Transaction Processing
System
Input Output
Process
Two Levels of Planning
? Systems Planning
– Gives Managers,Users,and Information
Systems Personnel Projects
– Establishes what should be done
– Sets a budget for the total cost of these projects
? Systems Project Planning
– Setting a plan for the development of each
specific systems project
Systems Professional Skills
? Systems Planning
– Form project team after proposed systems project is
cleared for development
? Systems Analysis
– Business Systems Analysts knowledgeable in business
? General Systems Design
– Business Systems Analysts
? Systems Evaluation and Selection
– Business Systems Analysts
? Detailed Systems Design
– Wide Range of Systems and Technical Designers
? Systems Implementation
– Systems analysts,programmers,and special
technicians
Effective Leadership Style
? Autocratic Style
– Crisis-Style Management
– Used to Correct Major Problem,such as Schedule
Slippage
? Democratic Style
– Team-oriented Leadership
– Gives each team member the freedom to achieve
goals which he/she helped set
? Laissez-Faire Style
– Highly-motivated,Highly-Skilled Team Members
– People who work best alone
Project Management Skills
? Planning
– States what should be done
– Estimates how long it will take
– Estimates what it will cost
? Leading
– Adapts to dynamics of enterprise and deals with setbacks
– Guides and induces people to perform at maximum
abilities
? Controlling
– Monitors Progress Reports and Documented Deliverables
– Compares Plans with Actuals
? Organizing
– Staffs a Systems Project Team
– Brings together users,managers,and team members
Project Management
? Gantt Chart
? Pert Chart
Gantt Chart
? Compares Planned Performance against
actual performance to determine whether
the project is ahead of,behind,or on
schedule
? Schedule a complete systems project by
phases
PERT Chart
? Four Steps
– Identify Tasks
– Determine Proper Sequence of Tasks
– Estimate the Time Required to Perform
each Task
– Prepare Time-Scaled Chart of Tasks and
Events to Determine the Critical Path
PERT Chart
? Estimate,Schedule,and Control a network of
interdependent tasks
? Shown by arrows,nodes,or circles
? Determine minimum time needed to complete a
project,phase,or task
? Critical Path
– Minimum time needed to complete a project
or phase
? Program,Evaluation and Renew Technique
– Total of the most time-consuming chain of
events
CASE
? Computer-Aided Systems and Software
Engineering
? Increase Productivity of Systems
Professionals
? Improve the Quality of Systems
Produced
? Improve Software Maintenance Issue
CASE
? Includes,
– workstations
– central repository
– numerous modeling tools
– project management
– Systems Development Life Cycle Support
– Prototyping Applications
– Software Design Features
Central Repository
? Models Derived from Modeling Tools
? Project Management Elements
? Documented Deliverables
? Screen Prototypes and Report Designs
? Software Code from Automatic Code
Generator
? Module and Object Libraries of Reusable
Code
? Reverse Engineering,Reengineering,and
Restructuring Features
Software Maintenance
? Reverse Engineering
– Extract original design from spaghetti-like,
undocumented code to make maintenance change
request
– Abstract meaningful design specifications that can be
used by maintenance programmers to perform
maintenance tasks
? Reengineering
– Examination and changing of a system to reconstitute it
in form and functionality
– Reimplementation
? Restructuring
– Restructures code into standard control constructs
? sequence,selection,repetition
Business Rules For Data
? Basic selection of what data elements are of
interest,what are their characteristics (data type
and acceptable range - also called syntactic
structure)
? How they are related to,or dependent on,each
other in a business sense (key,foreign key and
referential constraint rule - also called the
semantic structure)
? Data Integrity Rules
Data Rationalization
? Identification of data synonyms and
homonyms across multiple and disparate
data sources and the creation of a map that
points back to their original sources,
Data Access Gateway
? A system that sits between end users
(usually in PC networks) and a legacy
database,that accepts data read requests
(expressed as SQL statements),converts the
requests to legacy access method
instructions,and then provides the resulting
data to the users,The data flow is one-way
read-only,
Structured Analysis Identifies
? the functions or activities which are to be
handled by the system
? the external entities which interact with the
system
? the logical data stores,and
? the data flows among all the the above
? Data flow diagrams (DFD) are used to
diagrammatically describe the elements,
Conversion into Normalized
Record Types
? For every data flow which either enters or emanates from a data
store (in the leaf level DFDs),the integral data elements are
identified
? For every data store,a list of the data elements which are entering
and emanating are drawn up
? The dependencies among all the data elements are analyzed,and
the normalization rules are applied in steps so that at every step a
given relation is split into more,simple” relations
– Every relation has a key which consists of one or more data
elements
– Every non-key data element functionally depends on that entire
key and not on part of it
– No non-key data element depends on any other non-key data
element in the relation (there are no transitive dependencies)
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Conversion into Normalized
Record Types
Part Description for Model
for General Motors
“Part #123 that is supplied by GM was
assembled on bus 456 on May 28,1996” is
decomposed into the following elementary
sentences,
a),A part..,is supplied by a manufacturer..,
b),A part..,was assembled on a bus..,
c),The assembly [part*bus] was performed on
a date..,
Manufacturer
(name)
Supplier
of
Supplied
of
Part
(p#)
Part Distribution Model
for General Motors
Relationship Types
a),One-to-one (1:1),means that an occurrence
if one OT uniquely determines an occurrence
of other OT - and vice-versa
b),One-to-many (1:n),means that an
occurrence of one OT determines an
occurrence of the other OT - but not vice-
versa
c),Many-to-many (n:m):means that an
occurrence of one OT can be related to many
occurrences of other OT - and vice-versa
Bus
(License #) Part (p#)
Supplier
Manu-
facturer
(name)
Date of Assembly
Date
(Calc,
date)
Assembly Distribution Model
Normalization Model
? The SA/Normalization method is based on the use of
decomposition rules,which enable one to decompose
tables/relations,
– Database design starts with flat tables/relations,each of which is
created out of a data stores in the DFDs and then decomposed into the
normal form relations,No conceptual schema of the enterprise is
created to express the semantics of its information structure,
? The SA/IA method is based on the use of grouping rules which
map simple relationships in the binary-relationship data model
onto normal form relationships,
– The relational model and the normalization method have been criticized
for being too detailed to use at the initial design stage,and for lacking a
semantic structure for making unambiguous choices in modeling the
enterprise,
– The IA method incorporates a semantic model of the enterprise which
captures its essential semantic features from which the normal form
relations are derived,
? Basic selection of what data elements are of
interest,what are their characteristics (data
type and acceptable range - also called
syntactic structure)
? How they are related to,or dependent on,
each other in a business sense (key,foreign
key and referential constraint rule - also
called the semantic structure)
? Data Integrity Rules
Business Rules For Data
Data Rationalization
? Identification of data synonyms and
homonyms across multiple and disparate
data sources and the creation of a map that
points back to their original sources,
Data Access Gateway
? sits between end users (usually in PC
networks) and a legacy database
? accepts data read requests (expressed as
SQL statements)
? converts the requests to legacy access
method instructions
? provides the resulting data to the users
? data flow is one-way read-only,
Data Design
? Define all the entities to be dealt with and the relationships
between them
? Transform the conceptual design into logical design
wherein all the views are combined and all the resulting
data elements are defined and the data structure is
syntactically and semantically determined
? Normalize this logical design for mathematically
minimized redundancy and maximized integrity
? Transform this logical design to a physical design where
the underlying RDBMS,hardware,and use patterns are
taken into account
? Develop the SQL DDL code specific to each RDBMS
vendor’s product is generated
Data Warehouse
? An intermediate,read-only store (usually
based in a purchased RDBMS product) and
the programs that manage it,
? Contains recent and summarized data
extracted from across some or all of the
legacy data systems
? Presents a subject-based view
De-Normalization
? The process of selectively
– combining two or more normalized tables into
one,or
– decomposing one normalized table into two or
more
Entity Relationship Diagrams
(ERDs)
? A method of documenting and visualizing a
conceptual data model,
Functional Dependency
? Mathematical term for the key relationship
(using rational terminology) between data
elements,A data element (attribute) that is
functionally dependent on another data
element (the key) will always exist in a
relation (table) such that a unique value for
the key will always,determine” or,locate”
or,define a unique value of” the dependent,
Metadata
? Data about data that is generally extracted from an existing system or
created for a new system and stored in a design repository for
developers to use in maintaining or extending the system during its
lifecycle
? Metadata refers to the table,attribute,and key definitions contained
in the catalog of a relational database,It can also mean the business
rules for data designed for a new design,or the business rules for data
thought to be enforced in a legacy system (semantic data structure,
sometimes called meta-data,or meta2 data),
? The actual syntactic and semantic data structure (not just what the
documentation might say),including a complete synonym and
homonym map,plus the business rules for data that are actually being
enforced in the legacy system,
Normalization
? The process based on the business rules for
data
– a set of data elements (attributes) are arranged
in a mathematically minimum set of tables
(relations),within which all the attributes are
dependent on a primary key attribute (the key),
Relational Model
? The Relational Model for data design is the
foundation of the relational database and the
industry that produces the,engines” that
run them,
? It puts data design (and data modeling) on a
formal,mathematical footing,
Advantages of Data Query
?,slice and dice” dynamic query support
? standard high-level access language (SQL)
? minimum data redundancy
? self-protecting data integrity
– no insert,delete and update anomalies
GM Parts Example
“Part #123 that is supplied by GM was
assembled on bus 456 on May 28,1996”
is decomposed into the following
elementary sentences,
a),A part..,is supplied by a manufacturer..,
b),A part..,was assembled on a bus..,
c),The assembly [part*bus] was performed
on a date..,
Manufacturer
(name)
Supplier
of
Supplied
of
Part
(p#)
GM Parts Example
Relationship Types
a),One-to-one (1:1),means that an occurrence
if one OT uniquely determines an occurrence
of other OT - and vice-versa
b),One-to-many (1:n),means that an
occurrence of one OT determines an
occurrence of the other OT - but not vice-
versa
c),Many-to-many (n:m):means that an
occurrence of one OT can be related to many
occurrences of other OT - and vice-versa
Bus
(License #) Part (p#)
Supplier
Manu-
facturer
(name)
Date of Assembly
Date
(Calc,
date)
GM Parts Assembly Example