Trigger with multiple tables - sql

Question

I am trying to make a trigger that are going to take a value from one table and then make a subtraction with an other value in another table.
The trigger are going to operate in a table could (deposit), and then I would like to take the value that the user just inserted to the deposit table and subtract it with a value in another table(account). I have no problem to get following code to compile:
CREATE OR REPLACE TRIGGER aifer_insättning
AFTER INSERT
ON deposit
FOR EACH ROW
WHEN (new.belopp is not null)
BEGIN
UPDATE account SET SALDO = saldo + :new.belopp;
end;
/
But of course this update al the rows in the table account. I have tried everything to make it work with only one row, but I can´t get it. Does anyone have some suggestion hove I can resolve this?
Here is my tables:
SQL> desc account
Name Null? Type
----------------------------------------- -------- ------------
KNR NOT NULL NUMBER(8)
KTNR NOT NULL NUMBER(6)
REGDATUM NOT NULL DATE
SALDO NUMBER(10,2)
SQL> desc deposit
Name Null? Type
----------------------------------------- -------- ------------
RADNR NOT NULL NUMBER(9)
PNR NOT NULL VARCHAR2(11)
KNR NOT NULL NUMBER(8)
BELOPP NUMBER(10,2)
DATUM NOT NULL DATE

Answer 1

Presuming that the common column KNR is the primary key of ACCOUNT, I think the code you want is:
CREATE OR REPLACE TRIGGER aifer_insättning
AFTER INSERT
ON deposit
FOR EACH ROW
WHEN (new.belopp is not null)
BEGIN
UPDATE account a
SET a.SALDO = a.saldo + :new.belopp
WHERE a.knr - :new.knr;
end;
/
Note that I have added a table alias to make the code clearer.

Answer 2

Wouldn't you just need to add a where clause to the update statement in the trigger body? Or am I missing something?

Answer 3

delimiter $$
create trigger ss_ss before update on employee
for each row
begin
update consignee set
created_by = NEW.employee_pin
where created_by = OLD.employee_pin;
end
$$
delimiter ;
NOTE-> employee and consignee are two tables

Answer 4

**
Generate Triggers for all Tables
**
Well, I did this originally to generate triggers for all tables in a database to audit data changes, and that is simple enough, just move the entire row from the deleted table to a mirrored audit table.
But someone wanted to track activity on tables, so it's a little more simple. Here we create one log table, and any time a DML operation occurs, it is written there.
Enjoy
USE Northwind GO
CREATE TABLE LOG_TABLE (
Add_dttm datetime DEFAULT (GetDate()),
TABLE_NAME sysname,
Activity char(6)
);
GO
DECLARE
#sql varchar(8000),
#TABLE_NAME sysname SET NOCOUNT ON
SELECT #TABLE_NAME = MIN(TABLE_NAME)
FROM INFORMATION_SCHEMA.Tables
WHILE #TABLE_NAME IS NOT NULL
BEGIN
SELECT #sql = 'CREATE TRIGGER
[' + #TABLE_NAME + '_Usage_TR]
ON [' + #TABLE_NAME +'] '
+ 'FOR INSERT, UPDATE, DELETE AS '
+ 'IF EXISTS (SELECT * FROM inserted)
AND NOT EXISTS (SELECT * FROM deleted) '
+ 'INSERT INTO LOG_TABLE
(TABLE_NAME,Activity)
SELECT ''' + #TABLE_NAME + ''', ''INSERT''' + ' '
+ 'IF EXISTS (SELECT * FROM inserted)
AND EXISTS (SELECT * FROM deleted) '
+ 'INSERT INTO LOG_TABLE (TABLE_NAME,Activity) SELECT '''
+ #TABLE_NAME + ''', ''UPDATE''' + ' '
+ 'IF NOT EXISTS (SELECT * FROM inserted)
AND EXISTS (SELECT * FROM deleted) '
+ 'INSERT INTO LOG_TABLE (TABLE_NAME,Activity)
SELECT ''' + #TABLE_NAME + ''',
''DELETE''' + ' GO'
SELECT #sql EXEC(#sql)
SELECT #TABLE_NAME = MIN(TABLE_NAME)
FROM INFORMATION_SCHEMA.Tables
WHERE TABLE_NAME > #TABLE_NAME
END
SET NOCOUNT OFF