CREATE TRIGGER
Creates a trigger
DSQL, ESQL
CREATE TRIGGER trigname { <relation_trigger_legacy> | <relation_trigger_sql> | <database_trigger> | <ddl_trigger> } {<psql_trigger> | <external-module-body>} <relation_trigger_legacy> ::= FOR {tablename | viewname} [ACTIVE | INACTIVE] {BEFORE | AFTER} <mutation_list> [POSITION number] <relation_trigger_sql> ::= [ACTIVE | INACTIVE] {BEFORE | AFTER} <mutation_list> ON {tablename | viewname} [POSITION number] <database_trigger> ::= [ACTIVE | INACTIVE] ON <db_event> [POSITION number] <ddl_trigger> ::= [ACTIVE | INACTIVE] {BEFORE | AFTER} <ddl_event> [POSITION number] <mutation_list> ::= <mutation> [OR <mutation> [OR <mutation>]] <mutation> ::= INSERT | UPDATE | DELETE <db_event> ::= CONNECT | DISCONNECT | TRANSACTION {START | COMMIT | ROLLBACK} <ddl_event> ::= ANY DDL STATEMENT | <ddl_event_item> [{OR <ddl_event_item>} ...] <ddl_event_item> ::= {CREATE | ALTER | DROP} TABLE | {CREATE | ALTER | DROP} PROCEDURE | {CREATE | ALTER | DROP} FUNCTION | {CREATE | ALTER | DROP} TRIGGER | {CREATE | ALTER | DROP} EXCEPTION | {CREATE | ALTER | DROP} VIEW | {CREATE | ALTER | DROP} DOMAIN | {CREATE | ALTER | DROP} ROLE | {CREATE | ALTER | DROP} SEQUENCE | {CREATE | ALTER | DROP} USER | {CREATE | ALTER | DROP} INDEX | {CREATE | DROP} COLLATION | ALTER CHARACTER SET | {CREATE | ALTER | DROP} PACKAGE | {CREATE | DROP} PACKAGE BODY | {CREATE | ALTER | DROP} MAPPING <psql_trigger> ::= [SQL SECURITY {INVOKER | DEFINER}] <psql-module-body> <psql-module-body> ::= !! See Syntax of Module Body !! <external-module-body> ::= !! See Syntax of Module Body !!
Parameter | Description |
---|---|
trigname |
Trigger name.The maximum length is 63 characters.It must be unique among all trigger names in the database. |
relation_trigger_legacy |
Legacy style of trigger declaration for a relation trigger |
relation_trigger_sql |
Relation trigger declaration compliant with the SQL standard |
database_trigger |
Database trigger declaration |
tablename |
Name of the table with which the relation trigger is associated |
viewname |
Name of the view with which the relation trigger is associated |
mutation_list |
List of relation (table | view) events |
number |
Position of the trigger in the firing order.From 0 to 32,767 |
db_event |
Connection or transaction event |
ddl_event |
List of metadata change events |
ddl_event_item |
One of the metadata change events |
The CREATE TRIGGER
statement is used for creating a new trigger.A trigger can be created either for a relation (table | view) event (or a combination of relation events), for a database event, or for a DDL event.
CREATE TRIGGER
, along with its associates ALTER TRIGGER
, CREATE OR ALTER TRIGGER
and RECREATE TRIGGER
, is a compound statement, consisting of a header and a body.The header specifies the name of the trigger, the name of the relation (for a DML trigger), the phase of the trigger, the event(s) it applies to, and the position to determine an order between triggers.
The trigger body consists of optional declarations of local variables and named cursors followed by one or more statements, or blocks of statements, all enclosed in an outer block that begins with the keyword BEGIN
and ends with the keyword END
.Declarations and embedded statements are terminated with semicolons (‘;
’).
The name of the trigger must be unique among all trigger names.