Editing Database trigger (section)

===XML databases===
An example of implementation of triggers in non-relational database can be [[Sedna (database)|Sedna]], that provides support for triggers based on [[XQuery]]. Triggers in Sedna were designed to be analogous to [[SQL:2003]] triggers, but natively base on XML query and update languages ([[XPath]], [[XQuery]] and XML update language).

A trigger in Sedna is set on any nodes of an XML document stored in database. When these nodes are updated, the trigger automatically executes XQuery queries and updates specified in its body. For example, the following trigger cancels person node deletion if there are any open auctions referenced by this person:
<syntaxhighlight lang="xql">
CREATE TRIGGER "trigger3"
    BEFORE DELETE
    ON doc("auction")/site//person
    FOR EACH NODE
    DO
    {
        if (exists($WHERE//open_auction/bidder/personref/@person=$OLD/@id))
        then ( )
        else $OLD;
    }
</syntaxhighlight>