Management Information Systems, Sixth Edition

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Management Information Systems, Sixth Edition

• Chapter 7
• Databases and Data Warehouses

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Objectives

• Explain the difference between traditional file
  organization and the database approach to
  managing digital data
• Explain how relational and object-oriented
  database management systems are used to construct
  databases, populate them with data, and
  manipulate the data to produce information
• Enumerate the most important features and
  operations of a relational database, the most
  popular database model

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Objectives (continued)

• Understand how data modeling and design creates a
  conceptual blueprint of a database
• Discuss how databases are used on the Web
• List the operations involved in transferring data
  from transactional databases to data warehouses

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Managing Digital Data

• Businesses collect and dissect data for many
  purposes
• Data can be stored in database format
• Easy access and manipulation
• Databases have had a profound impact on business
• An information industry has been created
• Database technology integrated with the Internet
  has contributed to commerce significantly

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The Traditional File Approach

• Traditional file approach no mechanism for
  tagging, retrieving, or manipulating data
• Database approach provides powerful mechanism
  for managing and manipulating data
• Traditional approach is inconvenient
• Program-data dependency
• High data redundancy
• Low data integrity
• Data redundancy duplication of data
• Data integrity accuracy of data

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The Traditional File Approach (continued)
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The Database Approach

• Database approach data organized as entities
• Entity an object about which an organization
  chooses to collect data, such as
• People
• Events
• Products
• Character smallest piece of data
• A single letter or a digit
• Field single piece of information about entity

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The Database Approach (continued)

• Record collection of related fields
• File collection of related records
• Database fields can hold images, sounds, video
  clips, etc.
• Field name allows easy access to the data
• Database management system (DBMS) program used
  to
• Build databases
• Populate a database with data
• Manipulate data in a database

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The Database Approach (continued)

• Query a message to the database requesting data
  from specific records and/or fields
• Database must be properly secured
• Not everyone should have access to all data
• Users will have different views of the database,
  based on the data they are allowed to see

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The Database Approach (continued)

• Database administrator (DBA) the person
  responsible for managing the database
• Sets user limits for access to data in the
  database
• DBMS is usually bundled with a programming
  language

Management Information Systems, Sixth Edition
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Database Models

• Database model general logical structure
• How records stored in the database
• How relationships between records are established
• Database models differ in
• How records are linked to each other
• How users can navigate the database, retrieve
  records, and create records

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The Relational Model

• Relational Model consists of tables
• Based on relational algebra
• Tuple record (or row)
• Attribute field (or column)
• Relation table of records
• To design a relational database, you must
  understand the entities to be stored in the
  database and how they relate
• Tables are independent of each other, but can be
  related to each other

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The Relational Model (continued)

• Key a field whose values identify records
• Used to retrieve records
• Primary key a field by which records are
  uniquely identified
• Each record in the table must have a unique key
  value
• Composite key combination of fields that serve
  as a primary key

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The Relational Model (continued)
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The Relational Model (continued)

• Foreign key a field that is common to two tables
• Used to link the tables
• This field is a primary key in one table and a
  foreign key in the other
• Join table composite of tables
• Two types of table relationships
• One-to-many relationship one item in a table is
  linked to many items in the other table
• Many-to-many relationship many items in a table
  are linked to many items of the other table

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The Object-Oriented Model

• Object-oriented database model uses
  object-oriented approach for the database
  structure
• Encapsulation combined storage of data and
  relevant procedures to process it
• Allows object to be planted in different data
  sets
• Inheritance the ability to create a new object
  by replicating the characteristics of an existing
  (parent) object
• Object-oriented databases (ODBs) store data
  objects, not records

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Relational Operations

• Relational operation creates a temporary subset
  of a table or tables
• Used to create a limited list or a joined table
  list
• Three important relational operations
• Select a selection of records based on
  conditions
• Project a selection of certain columns from a
  table
• Join join data from multiple tables to create a
  temporary table

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Structured Query Language

• Structured Query Language (SQL) query language
  of choice for DBMSs
• Advantages of SQL
• It is an international standard
• It is provided with most relational DBMSs
• It has easy-to-remember, intuitive commands

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The Schema and Metadata

• Schema a plan that describes the structure of
  the database, including
• Names and sizes of fields
• Identification of primary keys
• Relationships
• Data dictionary a repository of information
  about the data and its organization
• Also called metadata the data about the data

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The Schema and Metadata (continued)

• Metadata includes
• Source of the data
• Tables related to the data
• Field and index information
• Programs and processes that use the data
• Population rules what is inserted, or updated,
  and how often

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Data Modeling

• Databases must be carefully planned and designed
  to meet business goals
• Data modeling analysis of an organizations data
  and identification of the data relationships
• A proactive process
• Develops a conceptual blueprint of the database
• Entity relationship diagram a graphical
  representation of all entity relationships

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Data Modeling (continued)

• Entity relationship diagram is composed of
• Boxes identify entities
• Lines indicate relationship between entities
• Crossbars indicate mandatory fields
• Circles indicate optional
• Crows feet identify many

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Data Modeling (continued)
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Data Modeling (continued)
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Databases on the Web

• Web is dependent on databases
• Organizations must link their databases to the
  Web
• Interface between Web and database required
• Interface may be programmed in one of several Web
  programming languages, including
• Java servlets
• Active server pages (ASP)
• PHP (Hypertext Preprocessor)
• Web application program interfaces (APIs)

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Databases on the Web (continued)
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Data Warehousing

• Most data collections are used for transactions
• Accumulation of transaction data is useful
• Data warehouse a large repository database that
  supports management decision making
• Typically relational
• Data is collected from transactional databases
• Data mart a smaller collection of data focusing
  on a particular subject or department

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From Database to Data Warehouse

• Transactional databases are not suitable for
  business analysis
• Contain only current, not historical data
• Data warehouse requires large storage capacity
• Mainframe computers are often used
• Scalability is an issue
• Data warehouses grow continually

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Phases in Data Warehousing

• Three phases in transferring data from a
  transactional database to a data warehouse
• Extraction phase create files from transactional
  database
• Transformation phase cleanse and modify the data
  format
• Loading phase transfer files to data warehouse
• A properly built data warehouse becomes a single
  source for all data required for analysis
• Data mining and online analytical processing
  (OLAP) use data in data warehouses

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Summary

• Organizations collect vast amounts of data
• Database approach has several advantages over
  traditional file approach
• Character smallest piece of data
• Field made up of multiple characters
• Record collection of related fields
• File collection of related records
• Database management system (DBMS) tool to
  construct databases

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Summary (continued)

• Relational and object-oriented database models
  have different advantages
• Keys are used to form links among entities
• Primary keys are unique identifiers
• Object-oriented database maintains objects that
  contain data and procedures that process it
• Structured Query Language (SQL) is an
  international standard for querying databases
• Database designer must construct a schema to
  construct a database

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Summary (continued)

• Database designers conduct data modeling and
  create entity relationship diagrams to plan
  databases
• Many databases are linked to Web
• Data warehouses contain huge collections of
  historical transaction data
• Data warehouse requires data extraction,
  transformation, and loading of transactional data
• Invasion of privacy is exacerbated by database
  technology