Basic HTML version of Foils prepared 7 October 97

Foil 34 Data Integrity in Oracle -II

From Untitled presentation ARL Database Tutorial -- February 98. by Gang Cheng, C.W. Ou, Geoffrey C. Fox
Integrity Constraints - a declarative way to define a business rule for a column of a table.
  • They are defined with a table and are stored as part of the table's definition
Following integrity constraints are supported by Oracle:
  • NOT NULL - disallow nulls (empty entries) in a table's column
  • UNIQUE - disallow duplicate values in a column or set of columns
  • PRIMARY KEY - disallow duplicate values and nulls in a column or set of columns
  • FOREIGN KEY - requires each value in a column or set of columns match a value in a related table's UNIQUE or PRIMARY KEY (FOREIGN KEY integrity constraints also define referential integrity actions that dictate what Oracle should do with dependent data if the data it references is altered)
  • CHECK - disallows values that do not satisfy the logical expression of the constraint

© Northeast Parallel Architectures Center, Syracuse University, npac@npac.syr.edu

If you have any comments about this server, send e-mail to webmaster@npac.syr.edu.

Page produced by wwwfoil on Tue Jan 27 1998