Power point

• Database


  An organized collection of related data
• Database systems


  • Can manage any form of data including text, images, sound and video
  • The most common database language is SQL (Structured Query Language)
  • Databases store and search data effectively
  • The most common type of database is the relational database, which stores information in tables
  • Databases are used extensively on the web

  
• Manual record keeping vs electronic databases

  Differences in format, data entry, organization, space requirements, accessibility, security, backup and disaster recovery, cost, search and analysis, updates
• Advantages of manual record keeping

  • Physical Format
  • Data Entry
  • Organization
  • Space Requirements
  • Accessibility
  • Security
  • Backup and Disaster Recovery
  • Cost
  • Search and Analysis
  • Updates
• Advantages of electronic databases

  • Digital Format
  • Data Entry
  • Organization
  • Space Requirements
  • Accessibility
  • Security
  • Backup and Disaster Recovery
  • Cost
  • Search and Analysis
  • Updates
• Why are databases useful?

  • Increase the speed and ease of information acquisition
  • Increase the quality of information acquired in terms of both accuracy and completeness
  • Improves the dissemination of information
• Relational database


  Data is divided into tables which are 'related' together
• Database Management System (DBMS)


  A software program that allows the user to create, manipulate, retrieve, and store information in a database
• Entity


  The real-world objects that are represented in the database
• Attributes


  Individual pieces of data about each entity
• Field


  An item of data within a record, made up of a number or characters. Has a field type and field size.
• Record


  Made up of a number of related fields
• Primary key


  One or more columns that uniquely identify each row in a table
• Foreign key


  A column, or set of columns, which creates a link between its table and another table
• Cardinality


  A number ratio expressed in symbols, like one-to-one or one-to-many
• Optionality


  Tells us whether or not a relationship is mandatory, or optional
• One-to-oneRelationship between two entities
• One-to-many


  Relationship between two entities
• Many-to-many


  Relationship between two entities
• Redundant data


  Any data that has more than one copy of it in the database
• Data validation and data integrity

  Ensuring data is accurate and consistent through type checking, range checking, limited options, required fields, mutually dependent fields, unique fields
• Data-entry errors


  Omission, substitution, transposition
• Error-trapping


  Visual check, verification check, validation check
• Query


  A field or option used to locate information within a database or another location
• SQL (Structured Query Language)

  1. SELECT and FROM

  2. WHERE and/or ORDER BY
• Database as a back-end to IT applications