Difference between revisions of "Databases"

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* Each attribute has a type (or domain)
 
* Each attribute has a type (or domain)
 
* All queries return relations (tables), so it can said to be compositional or closed.
 
* All queries return relations (tables), so it can said to be compositional or closed.
 +
 +
= XML Data =
 +
 +
* Alternative to relational model to store data
 +
* Standard for data representation and exchange
 +
* Document format similar to HTML, however tags represent content instead of formatting.

Revision as of 22:52, 7 December 2013

Relational Databases

  • Set of named relations (tables)
  • Each relation has a set of named attributes (columns)
  • Each tuple (row) has a value for each attribute
  • Each attribute has a type (or domain)
  • All queries return relations (tables), so it can said to be compositional or closed.

XML Data

  • Alternative to relational model to store data
  • Standard for data representation and exchange
  • Document format similar to HTML, however tags represent content instead of formatting.