Foreign Key - Referential Actions

Referential Actions

Because the database management system enforces referential constraints, it must ensure data integrity if rows in a referenced table are to be deleted (or updated). If dependent rows in referencing tables still exist, those references have to be considered. SQL:2003 specifies 5 different referential actions that shall take place in such occurrences:

  • CASCADE
  • RESTRICT
  • NO ACTION
  • SET NULL
  • SET DEFAULT

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