The Structure of Databases: Indexes (on Fields)

Scope

• Indexes contain in an ordered manner (usually a list) all the contents (information) of a particular field in every record in a database.
• Indexes speed searching of a database by enabling users to search relatively uniform lists of specific types of information rather than all of the fields in every record in the Database.
• A Database may have numerous Indexes.

Types of Indexes

• Indexes used in virtually all LAS (in descending order of preciseness):
  • Number Indexes (ISBN, Dewey Decimal Number, date)
  • Phrase Indexes (Title Index, Subtitle Index)
  • Subject Index (Library of Congress Subject Headings)
  • Author Index
  • Name Index
  • Keyword Indexes
• Some of the indexes that may be used in other databases

  author index	title index
  publisher index	subject headings index
  keyword index	abstract index
  page numbers index	publication date index
  volume number index	issue number index
  chemical formula index	image index

Organization of the contents of Indexes

• Indexes may be organized in several ways, including:
  • By date of entry
  • By numerical hierarchy
    • Examples:
      • ISBN, call numbers, publication date
  • By alphabetical ordering
    • Examples:
      • authors, titles, keywords, subjects

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