Newsgroup: it.comp.appl.access
Titolo: Triggers

Da un progetto di Access dovrei scrivere il codice di un Trigger su
Tabella1.
Cioč che in fase di insert,update e delete su Tabella1, mi modifichi
Tabella2.
Grazie anticipatamente a chi mi puň aiutare
Saluti Massimo


Posso solo riportarti quello che MSDN dice in proposito:
Triggers
Microsoft® SQL ServerT 2000 triggers are a special class of stored procedure
defined to execute automatically when an UPDATE, INSERT, or DELETE statement
is issued against a table or view. Triggers are powerful tools that sites
can use to enforce their business rules automatically when data is modified.
Triggers can extend the integrity checking logic of SQL Server constraints,
defaults, and rules, although constraints and defaults should be used
instead whenever they provide all the needed functionality.
Tables can have multiple triggers. The CREATE TRIGGER statement can be
defined with the FOR UPDATE, FOR INSERT, or FOR DELETE clauses to target a
trigger to a specific class of data modification actions. When FOR UPDATE is
specified, the IF UPDATE (column_name) clause can be used to target a
trigger to updates affecting a particular column.
Triggers can automate the processing for a company. In an inventory system,
update triggers can detect when a stock level reaches a reorder point and
generate an order to the supplier automatically. In a database recording the
processes in a factory, triggers can e-mail or page operators when a process
exceeds defined safety limits.
The following trigger generates an e-mail whenever a new title is added in
the pubs database:
CREATE TRIGGER reminder
ON titles
FOR INSERT
AS
   EXEC master..xp_sendmail 'MaryM',
      'New title, mention in the next report to distributors.'
Triggers contain Transact-SQL statements, much the same as stored
procedures. Triggers, like stored procedures, return the result set
generated by any SELECT statements in the trigger. Including SELECT
statements in triggers, except statements that only fill parameters, is not
recommended. This is because users do not expect to see any result sets
returned by an UPDATE, INSERT, or DELETE statement.
You can use the FOR clause to specify when a trigger is executed:
AFTER
The trigger executes after the statement that triggered it completes. If the
statement fails with an error, such as a constraint violation or syntax
error, the trigger is not executed. AFTER triggers cannot be specified for
views, they can only be specified for tables. You can specify multiple AFTER
triggers for each triggering action (INSERT, UPDATE, or DELETE). If you have
multiple AFTER triggers for a table, you can use sp_settriggerorder to
define which AFTER trigger fires first and which fires last. All other AFTER
triggers besides the first and last fire in an undefined order which you
cannot control.
AFTER is the default in SQL Server 2000. You could not specify AFTER or
INSTEAD OF in SQL Server version 7.0 or earlier, all triggers in those
versions operated as AFTER triggers.
INSTEAD OF
The trigger executes in place of the triggering action. INSTEAD OF triggers
can be specified on both tables and views. You can define only one INSTEAD
OF trigger for each triggering action (INSERT, UPDATE, and DELETE). INSTEAD
OF triggers can be used to perform enhance integrity checks on the data
values supplied in INSERT and UPDATE statements. INSTEAD OF triggers also
let you specify actions that allow views, which would normally not support
updates, to be updatable.
Negli stessi cd di MSDN potrai trovare molto, molto di più.
Ciao, Carlo