Download Chapter 4: Database Management

CSULB
IS 240 – 002 Fall 2001
A study guide for Midterm II
Chap. 4: Data Base Management
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Key Database Issues and Activities
• Entering and Querying Data
• Creating Database Reports
• Maintaining Data
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Entering and Querying Data
• Use a form for data entry
• Use queries to retrieve information
• Structured Query Language (SQL)
• Query by example (QBE)
• Creating Database Reports
• A compilation of data organized and produced in printed format
• DBMS packages include a report writer
• To Efficiently Maintain Data
• Model the data
• Select a physical structure
• Hierarchical
• Network
• Relational
• Normalization process
• Incl. Update / insert / delete procedures
• Data Modeling
• Ensures all needed data represented in the correct form,
• Identifies all the relationships that exists among data:
This is to remind you to emphasize certain areas while reviewing for
the exam. It does not represent every aspect of the exam. Make sure
you cover all areas but concentrate more in the topics listed.

•
“Associations”,
Communicates assumptions about the data and relationships with
the users of data.
• Associations
• Relationships among the entities in the data structures
• Three types
• One-to-one
• One-to-many
• Many-to-many
• Selecting a structure to store the data
• Hierarchical
• Network
• Relational
• Normalization
• A technique used to make complex databases more efficient
• Break one large table into several smaller tables
• Eliminates all repeating groups in records
• Eliminates redundant data
• Recent Developments
• Databases and Client-Server Computing
• Server holds the actual database
• Clients hold software to work with the database
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Object-Oriented Databases (OODBs)
• Treat tables, queries, etc., as reusable objects
• Data Mining (On-Line Analytical Processing)
– Drill down from summary data to detailed data
– Data Warehouses/Data Marts
• Integrates many large databases into one repository
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Linking Web Site Applications to Organizational Databases
• Users have Web view to organizational database
• Improves customer contact and service
• Adds security as a concern
Key Terms
• Databases: Collections of related data organized in a way that facilitates data
searches.
• Database management systems: Software applications with which you can
create, store, organize, and retrieve data for one or many databases.
• Entity: Things about which we collect data, such as people, courses,
customers, or products.
• Tables: Collections of related records about an entity type, where each row is
a record and each column is a field.
• Field: Individual pieces of information about an entity, such as a person’s last
name or social security number, stored in a database cell.
• Record: A collection of related fields about an entity, usually displayed as a
row in a database.
• Form: A collection of blank entry boxes, each representing a field, which is
used to enter information into a database.
• Querying: Requesting information from a database.
• Structured Query Language (SQL): The most common set of commands
used to request information from a database.
• Query by example (QBE): A capability of a DBMS to enable us to request
data by simply providing a sample or a description of the types of data we
would like to see.
• Report: A compilation of data that is organized and produced in a printed
format.
• Data model: A representation of entities and their relationships in the real
world.
• Primary key: A field included in a database that can be used to uniquely
identify each instance of an entity.
• Data type: Format for the data stored within a field.
• Data dictionary: A repository that describes data types, uses, storage
requirements, rules that affect data, and so on.
• Hierarchical database model: A DBMS approach in which entities are
described in a parent-child relationship.
• Network database model: A DBMS approach in which entities can have
multiple parent-child relationships.
• Relational database model: A DBMS approach in which entities are
presented as two-dimensional tables that can be joined together with common
columns
• Normalization: A process of making data structures simple and clear
• Client/server architecture: A distributed processing system in which a client
application that needs data or software gets it from a server that is a source for
some or all of the needed data or software.
• Database server: a powerful computer that contains the database and
responds to queries from client computers in a client/server application.
• Object-oriented databases: Database management systems that follow the
object-oriented approach of reusable objects, encapsulation, inheritance, and
so on.
• Data mining: Sorting and analyzing information stored in organizational
databases
• Data warehouses: Repositories integrating multiple large databases and
other informational sources in a single repository or access point that is
suitable for direct querying, analysis, or processing.
• Data marts: Small-scale data warehouses that contain a sub-set of the data
for a single aspect of a company’s business (for example, finance, inventory,
or personnel).
• Database administrator: Person responsible for the development and
management of the organization’s databases.
Chap. 9: Information Systems Development Process
•The Need for Structured Systems Development
• Systems Development
• Process of designing, building and maintaining information systems
• Performed by systems analysts
• Requires both managerial and technical expertise
•
•
The Evolution of Information Systems Development
Early days
• Techniques used to develop systems varied
• Difficult to integrate large systems
In response, IS professionals developed software engineering
• Easier to train programmers and analysts to use common techniques
• Results in more maintainable systems
• Options for Obtaining Information Systems
• Build internally by IS staff
• Buy a pre-packaged system
• Hire an organization or consultant to custom-build a system
• Users/departments build their own custom systems for their individual
needs (End-user development)
•Steps in the Systems Development Process
• Phase 1: System Identification, Selection, and Planning
• Undertake only those projects critical to mission, goals, and
•
•
objectives
Select a development project from all possible projects that could
be performed
Different evaluation criteria used to rank potential projects
• Phase 2: System Analysis
• Gain a thorough understanding of an organization’s current way of
•
•
doing things
Determine system requirements
• Interview users
• Develop questionnaires
• Watch the day-to-day activities of users
Organize information using data, process, and logic-modeling tools
• Phase 3: System Design
• The proposed system is designed
• Elements designed include
• Forms and reports
• Interfaces and dialogs
• Databases and files
• Processing and logic
• Phase 4: System Implementation
• Transform the design into a working system
• Software programming
• Testing
• Prepare organization to use the new system
• System conversion
• Documentation
• User training
• Support
• Phase 5: System Maintenance
• Largest part of system development effort
• Maintenance process
• Obtain maintenance request
• Transform requests into changes
• Design changes
• Implement changes
Key Terms
Systems analysis and design: The process of designing, building, and maintaining information
systems.
Systems analyst: The primary person responsible for performing systems analysis and design
activities.
Software engineering: A disciplined approach for constructing information systems through the
use of common methods, techniques, and tools.
Systems development life cycle (SDLC): The organizational process used to identify, design,
develop and maintain contemporary types of information systems.
Systems identification, selection, and planning: The first phase of the systems development life
cycle, in which potential projects are identified, selected, and planned.
Information systems planning: A formal organizational process for assessing the information
needs of an organization in which the systems, databases, and technologies for meeting those
needs are identified.
Tangible benefits: Benefits that are easily measured in dollars and with certainty.
Intangible benefits: Benefits that are not easily measured in dollars or with certainty.
Tangible costs: Costs that can be easily measured in dollars and with certainty.
Intangible costs: Costs that cannot be easily measured in dollars and with certainty.
One-time costs: Costs that occur once during the life of the system, typically during project
initiation.
Recurring costs: Costs associated with the ongoing evolution, use, and maintenance of a system.
System analysis: The second phase of the systems development life cycle, in which the current
ways of doing business are studied and alternative replacement systems are proposed.
Data flows: Data in motion, moving from one place in the system to another.
Processing logic: The steps by which data is transformed or moved and a description of the events
that trigger these steps.
System design: The third phase of the systems development life cycle, in which all features of the
proposed system are described.
Form: A business document that contains some predefined data and may include some areas
where additional data is to be filled in, typically for a single record.
Report: A business document that only contains predefined data that is used for reading and
viewing, typically for multiple records.
Pseudo code: A textual notation for describing programming code.
Structure charts: Hierarchical diagram that shows how an information system is organized.
Decision trees: A graphical representation of a decision situation.
System implementation: The fourth phase of the systems development life cycle, in which the
information system is programmed, tested, installed, and supported.
Developmental testing: Testing performed by programmers to assure that each module is error
free.
Alpha testing: Testing performed by the development organization to assess whether the entire
system meets the design requirements of the users.
Beta testing: Testing performed by actual system users, who test the capabilities of the system
with actual data in the users’ work environment.
System conversion: The process of decommissioning the current system and installing
the new system into the organization.
Parallel conversion: Changing over from the old to a new system by running both at the same
time until the organization is sure that the new system is error free, that the users are
adequately trained, and that the support procedures are in place.
Direct conversion: Changing over from the old to a new system by beginning the new system and
discontinuing the old at the same time.
Phased conversion: Changing over from the old to a new system by utilizing parts of the new
system and adding new modules and features to the new system as each part is validated as
working properly. Process continues until the entire system is operating and the old system is
replaced.
Pilot conversion: Changing over from the old to a new system by running the entire system in one
location until it is validated as operating properly. The system is then diffused into the entire
organization.
Maintenance phase: Phase in which a person from the systems development group
collects maintenance requests from system users.
System maintenance: The fifth (and final) phase of the systems development life cycle, in which
an information system is systematically repaired and/or improved.
Corrective maintenance: Making changes to an information system to repair flaws in the design,
coding, or implementation of the system.
Adaptive maintenance: Making changes to an information system to evolve its functionality to
changing business needs or to migrate it to a different operating environment.
Perfective maintenance: Making enhancements to improve processing performance, interface
usability, or to add desired, but not necessarily required, system features.
Preventive maintenance: Making changes to a system to reduce the chance of future system
failure.
Chap. 10: Contemporary Information Systems Development
Approaches
• Contemporary Methods for Collecting and Structuring System Requirements
• Critical Success Factors (CSF)
• Joint Application Requirements (JAR)/Joint Application Design
(JAD)
• Contemporary Approaches for Designing and Building Systems
• Prototyping
• Rapid Application Development
• Object-Oriented Analysis and Design
• Tools for Supporting Contemporary Systems Development
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Computer Aided Software Engineering (CASE)
Group Support Systems
Advanced Programming Languages
Key Terms
Critical Success Factor (CSF): A methodology for collecting system requirements that helps
identify the few things that must go well to ensure success for a manager or organization.
Joint Application Requirements and Joint Application Design: Group-based methods for
collecting requirements and creating system designs.
Facilitator: An expert at running JAD meetings who helps the group work effectively during the
session.
Scribe: A person who attends a JAD meeting to record the meeting information.
Prototyping: An iterative systems development process in which requirements are converted to a
working system, which is continually revised through close work between analysts and users.
Rapid Application Development: A systems development methodology that combines
prototyping, computer-based development tools, special management practices, and close
user involvement.
Object-Oriented Analysis and Design (OOA&D): Systems development methodologies and
techniques based on objects rather than data or processes.
Computer-Aided Software Engineering: Software tools that provide automated support for some
portion of the systems development process.
Upper CASE: CASE tools designed to support the system identification, selection, and planning;
system analysis; and system design phases of the systems development life cycle.
Lower CASE: CASE tools designed to support the implementation and maintenance phases of the
systems development life cycle.
Visual programming: The use of programming languages, which facilitate the development of
graphical user interfaces with such tools as drag-and-drop icons and pop-up menus.
Object-oriented programming: The use of programming languages that rely on reusable objects,
which encapsulate data and logic, as the building blocks for programs.
Fourth-generation languages: Non-procedural, English-like languages that require the user to
describe the desired output rather than the procedure needed to generate it.