Basic HTML version of Foils prepared 7 October 97

Foil 5 Some Basic Terminology for Relational Database Model

From untitled presentation ARL Database Tutorial -- February 98. by Gang Cheng, C.W. Ou, Geoffrey C. Fox
1 Data Structure
  • relations (files, tables)
  • tuples (records, rows)
  • attributes (fields, columns)
2 Relation operators
  • scan (select-project) (one or more tables , a condition to satisfy, and an attribute list)
  • sort (reorder)
  • aggregate operators (SUM,AVG,MAX,MIN,...)
  • insert/delete/update modification of tables
  • set operators (union, intersection, difference)
  • join, merge and division
  • operators can be embedded recursively with the characteristics:
    • uniformity of the data and operators as input and output is same data object (feature of 4GL)
    • source of data-flow execution model
in Table To:

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