Week 3 Flashcards
Database System Development Lifecycle
Database planning
System definition
Requirements collection and analysis
Database design
DBMS selection (optional)
Application design
Prototyping (optional)
Implementation
Data conversion and loading
Testing
Operational maintenance
Management activities that allow stages of database system development lifecycle to be realized as efficiently and effectively as possible.
Must be integrated with overall IS strategy of the organization.
Database planning
_______for the database project defines major aims of database application.
Those driving database project normally define the _
_______ .
database planning - mission statement
_______ helps clarify purpose of the database project and provides clearer path towards the efficient and effective creation of required database system.
Mission statement
Once mission statement is defined, _____ are defined.
Each ______ should identify a particular task that the database must support.
May be accompanied by some additional information that specifies the work to be done, the resources with which to do it, and the money to pay for it all.
mission objectives
Database planning should also include development of standards that govern:
how data will be collected,
how the format should be specified,
what necessary documentation will be needed,
how design and implementation should proceed.
Describes scope and boundaries of database system and the major user views.
User view defines what is required of a database system from perspective of:
a particular job role (such as Manager or Supervisor) or
enterprise application area (such as marketing, personnel, or stock control).
system definition
Database application may have one or more _____
Identifying ______ helps ensure that no major users of the database are forgotten when developing requirements for new system.
____ also help in development of complex database system allowing requirements to be broken down into manageable pieces.
User views
Process of creating a design for a database that will support the enterprise’s mission statement and mission objectives for the required database system.
database design
Main approaches in database design nclude:
Top-down
Bottom-up
Inside-out
Mixed
Main purposes of data modeling include:
to assist in understanding the meaning (semantics) of the data;
to facilitate communication about the information requirements.
Building data model requires answering questions about __,____, and ____
entities, relationships, and attributes.
A data model ensures we understand:
- each user’s perspective of the data;
- nature of the data itself, independent of its physical representations;
- use of data across user views.
Criteria to Produce an Optimal Data Model
structural validity
simplicity
expressibility
nonredundancy
shareability
extensibility
integrity
diagrammatic representation
Three phases of database design:
Conceptual database design
Logical database design
Physical database design.
Process of constructing a model of the data used in an enterprise, independent of all physical considerations.
Data model is built using the information in users’ requirements specification.
conceptual database design
_____ is source of information for logical design phase.
Conceptual data model
Process of constructing a model of the data used in an enterprise based on a specific data model (e.g. relational), but independent of a particular DBMS and other physical considerations.
Logical database design
Conceptual data model is refined and mapped on to a _____.
logical data model
Process of producing a description of the database implementation on secondary storage.
Describes base relations, file organizations, and indexes used to achieve efficient access to data. Also describes any associated integrity constraints and security measures.
Tailored to a specific DBMS system.
Physical Database Design
Selection of an appropriate DBMS to support the database system.
Undertaken at any time prior to logical design provided sufficient information is available regarding system requirements.
DBMS Selection
Main steps to selecting a DBMS:
define Terms of Reference of study;
shortlist two or three products;
evaluate products;
recommend selection and produce report.
Design of user interface and application programs that use and process the database.
Database design and application design are parallel activities.
Application design
Includes two important activities in application design:
transaction design;
user interface design.