Editing Database trigger (section)

=== Oracle ===
In addition to triggers that fire (and execute [[PL/SQL]] code) when data is modified, [[Oracle Database|Oracle 10g]] supports triggers that fire when schema-level objects (that is, tables) are modified and when user logon or logoff events occur.

==== Schema-level triggers ====

* After Creation
* Before Alter
* After Alter
* Before Drop
* After Drop
* Before Insert

The four main types of triggers are:
# Row-level trigger: This gets executed before or after ''any column value of a row'' changes.
# Column-level trigger: This gets executed before or after the ''specified column'' changes.
# For each row type: This trigger gets executed once for each row of the [[result set]] affected by an insert/update/delete.
# For each statement type: This trigger gets executed only once for the entire result set, but also fires each time the statement is executed.

==== System-level triggers ====
From [[Oracle8i|Oracle 8i]], database events - logons, logoffs, startups - can fire Oracle triggers.<ref>
{{cite book
| last1 = Nanda
| first1 = Arup
| last2 = Burleson
| first2 = Donald K.
| chapter = 9
| editor1-last = Burleson
| editor1-first = Donald K.
| title = Oracle Privacy Security Auditing: Includes Federal Law Compliance with HIPAA, Sarbanes Oxley and the Gramm Leach Bliley Act GLB
| url = https://books.google.com/books?id=Gm2hzeWhou0C
| series = Oracle in-focus series
| year = 2003
| volume = 47
| location = Kittrell, North Carolina
| publisher = Rampant TechPress
| publication-date = 2003
| page = 511
| isbn = 9780972751391
| access-date = 2018-04-17
| quote = [...] system-level triggers [...] were introduced in Oracle8i. [...] system-level triggers are fired at specific system events such as logon, logoff, database startup, DDL execution, and servererror [...].
}}
</ref>