Part 2 in the DBMS Series. Focusing on the Database Development Lifecyle

1. Database Management
Systems
The Database DevelopmentLife Cycle
By Nickkisha Farrell, BSc IT, Dip Ed
January 2014

2. IN THIS PRESENTATION
Information Systems and The SDLC
Database Development
The Database Life Cycle
Conceptual, Logical and Physical Data Models
Summary
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3. INFORMATION SYSTEMS
• Allows for data collection, storage, and retrieval
• Facilitates the transformation of data into information and
the management of data and information
Hardware & Software
Databases
Information Systems
Services
Networking
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4. Systems Development
• Process of creating and maintaining an IS/software.
• The development process is divided into a series of phases.
• The collection of phases is known as the development lifecycle.
• The software product moves through this life cycle until it is
finally retired from use.
• Ideally, each phase in the life cycle can be checked for
correctness before moving on to the next phase
• The waterfall model is a popular model of development
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5. SYSTEMS DEVELOPMENT LIFECYCLE (SDLC)
• Establishing Requirements
• consultation with, and agreement
among, stakeholders as to what they want
of a system, expressed as a statement of
requirements.
• Feasibility Study is conducted
• Should the existing system be:
Continued? | Modified? | Replaced?
• System Cost estimated
Planning
Analysis
Detailed
System Design
Implementation
Maintenance
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6. SYSTEMS DEVELOPMENT LIFECYCLE (SDLC)
• Analysis starts by considering the
statement of requirements and finishes
by producing a system specification. The
specification is a formal representation
of what a system should do, expressed
in terms that are independent of how it
may be realized
User Requirements
Existing System Evaluation
Logical System Design
Planning
Analysis
Detailed
System Design
Implementation
Maintenance
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7. SYSTEMS DEVELOPMENT LIFECYCLE (SDLC)
•Detailed Specifications
•Screen, menu, report layouts
•Conversion from old to new
• Design begins with a system
specification and produces
design documents, and provides
a detailed description of how a
system should be constructed.
Planning
Analysis
Detailed
System Design
Implementation
Maintenance
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8. SYSTEMS DEVELOPMENT LIFECYCLE (SDLC)
• Implementation is the construction of a computer system
according to a given design document and taking account of
the environment in which the system will be operating.
Planning
Analysis
• Testing compares the implemented system against the design
documents and requirements specification and produces an
acceptance report or, more usually, a list of errors and bugs
that require a review of the analysis, design and
implementation processes to correct
 Usually the task that leads to the waterfall model
iterating through the life cycle).
Coding
Testing
Debugging
Installation
Detailed
System Design
Implementation
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Maintenance

9. SYSTEMS DEVELOPMENT LIFECYCLE (SDLC)
• Involves dealing with changes in the
requirements, or the implementation
environment, bug fixing or porting of the
system to new environments (for example
migrating a system from a standalone PC to
a networked environment).
Evaluation
Maintenance
System Errors
Business Changes
Enhancements
Planning
Analysis
Detailed
System Design
Implementation
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Maintenance

10. GETTING DATABASE DESIGN RIGHT
• Uncontrolled ad hoc creation of tables by end users may
lead to an unmanageable and unusable database
environment.
• Resulting in the inclusion of multiple copies of potentially
inconsistent data.
• Thus when creating databases there is a need for a
methodical approach to development
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11. DESIRABLE PROPERTIES OF A DATABASE
Completeness
Integrity
Flexibility
Efficiency
Usability (ease of use)
Ensures that users can access the data they want. Note
that this includesad hoc queries, which would not be
explicitly given as part of a statement of data
requirements.
Ensures that data is both consistent (no contradictory
data) and correct (no invalid data), and ensures that
users trust the database.
Ensures that a database can evolve (without requiring
excessive effort) to satisfy changing user requirements.
Ensures that users do not have unduly long response
times when accessing data.
Ensures that data can be accessed and manipulated in
ways which match user requirements.
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12. DATABASE DEVELOPMENT
• Not just a matter of creating tables that seem to
match the way you see data on forms or reports.
• Requires a detailed understanding of the meaning of
the data and their relationships to ensure that a
database has the right properties.
• Thus data analysis, which is concerned with
representing the meaning of data as a conceptual
data model, must be performed.
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13. DATABASE DEVELOPMENT
• Process of database design and development
• Database Design
• Complete, normalized, non-redundant and fully
integrated conceptual, logical, and physical database
models
• Database Implementation
• Database storage structure, loading data, and data
management
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14. STAGES OF THE DATABASE LIFECYLE
Gathering
Requirements
Database
Analysis
Database
Maintenance
Database
Testing and
Evaluation
Database
Design
Database
Implementation
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15. STAGES OF THE DATABASE LIFECYLE
• The database designer/s interview the customers (database users)
• Obtains and documents the data and functional requirements.
• The result: document including the detail requirements provided by
the users
• Document contains data they want to store along with an agreement
as to the meaning and interpretation of the data elements.
• To make sure that it is easily understood, it should not be overly
formal or highly encoded.
Gathering
Requirements
Database
Analysis
Database
Maintenance
Database
Testing and
Evaluation
• The requirements should not describe how the data is to be processed, but rather
what the data items are, what attributes they have, what constraints apply and the
relationships that hold between the data items.
Database
Design
Database
Implementation
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16. STAGES OF THE DATABASE LIFECYLE
Data analysis begins with the statement of data
requirements and then produces a conceptual data model.
Gathering
Requirements
Database
Maintenance
- aim is to obtain a detailed description of the data that will
suit user requirements.
- these include properties such as the possible range of
values that can be permitted for attributes such as, in the
School Database example; the Student course
code, course title and credit points.
Database
Analysis
Database
Design
Database Testing
and Evaluation
A conceptual data model is concerned with the meaning and structure of
data, but not with the details affecting how they are implemented.
Analysis focuses on ‘What is required?’ not ‘How is it achieved?
Database
Implementation
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17. STAGES OF THE DATABASE LIFECYLE
• The database design phase is divided into
three steps:
- conceptual database design
- logical database design
- physical database design
Gathering
Requirements
Database
Maintenance
Database
Analysis
Database
Design
Database Testing
and Evaluation
Conceptual Design Phase - the model of
the data to be used is independent of all
physical considerations is to be constructed.
The model is based on the requirements
specification of the system.
Database
Implementation
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18. STAGES OF THE DATABASE LIFECYLE
• Logical Design Phase - the model of the data
to be used is constructed, while based on a
specific data model, it remains independent of a
particular database management system.
• e.g. relational data model.
• Physical Design Phase - the description of the
implementation of the database on secondary
storage is created. The base
relations, indexes, integrity
constraints, security, etc. are defined using the
SQL language.
Gathering
Requirements
Database
Maintenance
Database
Analysis
Database
Design
Database Testing
and Evaluation
Database
Implementation
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19. DATABASE DESIGN
Feature
Conceptual
Logical
Entity Names
✓
✓
Entity
Relationships
✓
Physical
✓
Attributes
✓
Primary Keys
✓
✓
Foreign Keys
✓
✓
Table Names
✓
Column Names
✓
Column Data
Types
✓
• There are three
levels of data
modeling
 Conceptual
 Logical
 Physical
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20. DATABASE DESIGN
Conceptual
Logical
Physical
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21. STAGES OF THE DATABASE LIFECYLE
• Realising the design
 Install the selected DBMS
 Create the databases
 Populating the database
Gathering
Requirements
Database
Maintenance
Database
Analysis
Database
Design
Database Testing
and Evaluation
• Supporting users and user processes
• Supporting data management strategies
Database
Implementation
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22. STAGES OF THE DATABASE LIFECYLE
The aim of testing is to uncover errors in the design and
implementation of the database. Testing is usually
Database
Maintenance
considered to involve two main tasks – validation and
verification.
Validation answers the question: has the right
database been developed to meet the requirements?
Verification answers the question: has the database
design been implemented correctly?
Gathering
Requirements
Database
Analysis
Database Testing
and Evaluation
Database
Design
Database
Implementation
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23. STAGES OF THE DATABASE LIFECYLE
• Operational maintenance Gathering
Requirements
• Performance of the database is monitored.
Database
• If it falls below some acceptable standard, re-organisation Maintenance
of the database, takes place to ensure that performance is
maintained at an acceptable level.
• Porting and implementation maintenance
Database Testing
and Evaluation
• The DBMS, user processes, underlying computer system
Database
or some other aspect undergoes changes that require the
Implementation
database implementation to be revised.
• Requirements change - original requirement specification changes.
• Typically involves a ‘mini life cycle’ related to the development of
changes to meet the new requirements.
Database
Analysis
Database
Design
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24. SUMMARY
• Database Development requires careful planning
and organization.
• The DBLC is an instance of the popular SDLC, in this
presentation particularly the waterfall model.
• Each stage of development is directly dependent on
the previous.
• Stages of development may sometimes iterate.
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25. REFERENCES
• Gillenson, Mark L.,2012, Fundamentals of Database
Management Systems / Mark L. Gillenson.—2nd ed., John
Wiley and sons inc
• http://www.open.edu/openlearn/science-mathstechnology/computing-and-ict/information-andcommunication-technologies/the-database-developmentlife-cycle/content-section-1.1
• http://bccampus.pressbooks.com/dbdesign/chapter/chapte
r-13-database-application-development-process/
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