To create a new trigger in SQLite, you use the statement to update 10 rows in a table, the trigger that associated with the table is fired 10 times. If the trigger associated with the table is fired one time, we call this trigger a FOR EACH STATEMENT trigger.
As of version 3.9.2, SQLite only supports FOR EACH ROW triggers.
A database trigger is procedural code that is automatically executed in response to certain events on a particular table or view in a database.
The trigger is mostly used for maintaining the integrity of the information on the database.
You can add triggers to columns in your board view to automatically change properties when a card is moved to that column.
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Notice that if you drop a table, all associated triggers are also deleted.
create trigger biu_parts for parts before insert or update as begin /* conditional code when inserting: */ if (inserting and is null) then = gen_id(gen_partrec_id, 1); /* common code: */ new.partname_upper = upper(new.partname); end In Firebird 2.0 only, a restriction is in place which prevents anyone from dropping, altering or recreating a trigger or stored procedure if it has been used since the database was opened.
For example, when a new record (representing a new worker) is added to the employees table, new records should also be created in the tables of the taxes, vacations and salaries.
Triggers can also be used to log historical data, for example to keep track of employees' previous salaries.
It has not yet supported the FOR EACH STATEMENT triggers.