Information system ralph CH03

Fundamentals of Information
Systems, Fifth Edition
Chapter 3
Database Systems and Business
Intelligence


Principles and Learning Objectives
• Data management and modeling are key aspects
of organizing data and information
– Define general data management concepts and
terms, highlighting the advantages of the database
approach to data management
– Describe the relational database model and outline
its basic features

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Principles and Learning Objectives
(continued)
• A well-designed and well-managed database is an
extremely valuable tool in supporting decision
making
– Identify the common functions performed by all
database management systems, and identify popular
database management systems

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Principles and Learning Objectives
(continued)
• The number and types of database applications will
continue to evolve and yield real business benefits
– Identify and briefly discuss current database
applications

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Data Management
• Without data and the ability to process it
– An organization could not successfully complete
most business activities

• For data to be transformed into useful information,
it must first be organized in a meaningful way

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The Hierarchy of Data

• Bit
– Circuit that is either on or off
– Eight bits = one byte

• Character
– Basic building block of information

• Field
– Name, number, or combination of characters that
describes an aspect of a business object or activity

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The Hierarchy of Data (continued)
• Record
– Collection of related data fields

• File
– Collection of related records

• Database
– Collection of integrated and related files

• Hierarchy of data
– Bits, characters, fields, records, files, and databases

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Data Entities, Attributes, and Keys
• Entity
– Generalized class of people, places, or things for
which data is collected, stored, and maintained

• Attribute
– Characteristic of an entity

• Data item
– Value of an attribute

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Data Entities, Attributes, and Keys
(continued)
• Key
– Field or set of fields in a record that is used to
identify the record

• Primary key
– Field or set of fields that uniquely identifies the
record

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The Database Approach
• Traditional approach to database management
– Separate data files are created and stored for each
application program

• Database approach to database management
– Multiple application programs share a pool of related
data

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Data Modeling and Database
Characteristics
• When building a database, consider:
– Content: What data should be collected, at what
cost?
– Access: What data should be provided to which
users and when?
– Logical structure: How should data be arranged to
make sense to a given user?
– Physical organization: Where should data be
physically located?

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Data Modeling
• Building a database requires two types of designs
– Logical design
• Abstract model of how data should be structured and
arranged to meet an organization’s information needs

– Physical design
• Fine-tunes the logical database design for
performance and cost considerations

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Data Modeling (continued)
• Planned data redundancy
– Improves system performance

• Data model
– Diagram of data entities and their relationships

• Enterprise data modeling
– Data modeling done at the level of the entire
enterprise

• Entity-relationship (ER) diagrams
– Data models that use basic graphical symbols to show
the organization of and relationships between data

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The Relational Database Model
• Relational model
– Describes data using a standard tabular format
– Data elements are placed in two-dimensional tables,
called relations, the logical equivalent of files

• Domain
– Allowable values for data attributes

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Manipulating Data

• Selecting
– Eliminates rows according to criteria

• Projecting
– Eliminates columns in a table

• Joining
– Combines two or more tables

• Linking
– Combines two or more tables using common data
attributes
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Database Management Systems
(DBMS)
• Group of programs used as an interface between a

database and application programs or a database
and the user
• Used to manage all kinds of data for all kinds of
purposes

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