Skip to main content

hierarchical data model

hierarchical data model A data model based on one–many relationships between aggregations of fixed numbers of data items, such an aggregation being termed a segment. A database record type comprises a number of segment types, arranged in a hierarchy, commencing with the root segment type; below the root segment type there is zero, one, or more segment types at the first level, with a similar structure below each of these first-level types at the second level, and so on. Thus each segment type except the root is dependent on a segment type at the immediately higher level. A database record instance comprises a single instance of the root segment type and zero, one, or more instances of each of its types at the first level. Corresponding to each of these first-level instances, there will be zero, one, or more instances of each of the appropriate second-level types, and so on. Only the root segment can have an independent existence.

IMS, an important database management system supplied by IBM, is based on and implements this data model.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"hierarchical data model." A Dictionary of Computing. . Encyclopedia.com. 21 Aug. 2018 <http://www.encyclopedia.com>.

"hierarchical data model." A Dictionary of Computing. . Encyclopedia.com. (August 21, 2018). http://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/hierarchical-data-model

"hierarchical data model." A Dictionary of Computing. . Retrieved August 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/hierarchical-data-model

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.