CHAPTER 5 MANAGING ORGANIZATIONAL DATA AND INFORMATION

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CHAPTER 5MANAGING ORGANIZATIONAL DATA AND
INFORMATION
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Basics of Data Arrangementand Access

• The Data Hierarchy
• Field - a logical grouping of characters into a
  word, a small group of words, or a complete
  number
• Record - a logical grouping of related fields
• File - a logical grouping of related records
• Database - a logical grouping of related files
• Entity - a person, place, thing, or event about
  which information is maintained
• Attribute - each characteristic or quality
  describing a particular entity
• Primary Key - field that uniquely identifies the
  record
• Secondary Key - field that has some identifying
  information, but typically does not identify the
  file with complete accuracy

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Problems with Traditional File Approach

• data redundancy
• data inconsistency
• data isolation
• security
• data integrity
• application/data independence

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Database The Modern Approach

• Creating a Database
• Conceptual design - an abstract model of the
  database from the user or business perspective
• Physical design - shows the way a database is
  actually arranged with a storage devices
• Entity-relationship (ER) modeling
• process of planning the database design
• Entity classes ? Instance ? Identifiers ?
  Relationships
• Normalization
• method for analyzing and reducing a relational
  database to its most streamlined form for minimum
  redundancy, maximum data integrity, and best
  processing performance

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Database Management Systems

• A software program (or group of programs) that
  provides access to a databases
• Permits an organization to store data in one
  location, from which it can be updated and
  retrieved
• Provides access to the stored data by various
  application programs
• Provides mechanisms for maintaining the integrity
  of stored information, managing security and user
  access, recovering information when the system
  fails, and accessing various database functions
  form within an application written in a
  third-generation, fourth-generation, or
  object-oriented language

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DBMS Components

• 4 Main Components
• Data model
• defines the way data are conceptually structured
• Data definition language (DDL)
• defines what types of information are in the
  database and how they will be structured
• functions of the DDL
• provide a means for associating related data
• indicate the unique identifiers (or keys) of the
  records
• set up security access and change restrictions

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DBMS Components (continued )

• Data manipulation language (DML)
• Structured query language (SQL) - most popular
  relational database language
• Data Dictionary
• stores definitions of data elements and data
  characteristics

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Company Data Models