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Chapter 4: Database
Management
Data
People
Information
Systems
Hardware
Telecommunications
Software
Databases Before the Use of
Computers
• Data kept in books, ledgers, card files,
folders, and file cabinets
• Long response time
• Labor-intensive
• Often incomplete or inaccurate
Key Database Issues
and Activities
• Entering and Querying Data
• Creating Database Reports
• Maintaining Data
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
• Report
– A compilation of data organized and
produced in printed format
• DBMS packages include a report writer
• Graphics can be added
• Can be automatically updated by linking
to data
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: “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
- U.S. Airways • The fifth largest airline in America, U.S.
Airways--with 2500 jet flights per day--is
using an IBM database system to better
manage its in-flight meal and video
services. By analyzing upgrade, noshow, and cancellation patterns, U.S.
Airways can more accurately predict
how many meals are needed on each
flight. … (page 2-92)
Selecting a physical structure
in which to store the data
• Hierarchical
• Network
• Relational
The Hierarchical Model
The Network Model
The Relational Model
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
Redundant Data
Normalized Data
Logical vs. physical
representation of data
• The same “number” can be:
– An invoice number in sales
– A billing number in accounting
– A picking number in warehouse
– A delivery ticket number in distribution
Recent Developments
• Databases and Client-Server Computing
– Server holds the actual database
– Clients hold software to work with the
database
Client/Server Database
Recent Developments
• Object-Oriented Databases (OODBs)
– Treat tables, queries, etc., as reusable
objects
Recent Developments
• 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
• Table 4.3 Sample industry uses of data
warehousing (adapted from: Boar, 1998).
Recent Developments
• Linking Web Site Applications to
Organizational Databases
– Users have Web view to organizational database
– Improves customer contact and service
– Adds security as a concern
- CNN Interactive • An example of successfully linking a
large corporate database with a Web
interface can be found at CNN
Interactive. CNN Interactive provides a
free, online custom news service to
hundreds of thousands of subscribers
around the world. … (page 2-109)
Effective Management of
Databases
• Database Administrator (DBA)
– Responsible for the development and
management of an organization’s
databases
• Works with systems analysts on design
• Works with users and managers on
managerial and organizational issues
• Responsible for implementing security
features
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 twodimensional 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 objectoriented 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.