Oracle Trigger to replace values in a record - oracle

I want to update the inserted value in a column from a table but only if it matches a value from a different column.
So both records are in the same table but we only want to update the value test_id if the test_lead_id corresponds with certain values.
I am trying this but with no luck....
`CREATE OR REPLACE TRIGGER test_trigger
BEFORE INSERT ON "test_list"
FOR EACH ROW BEGIN
IF :old.test_id = '1000' then
:new.test_id := '2000'
WHEN test_lead_id in ('150','151');
END IF;
END;
`
Any help is appreciated.
Many thanks

There is no old value for an insert statement. Try this:
CREATE OR REPLACE TRIGGER test_trigger
BEFORE INSERT ON "test_list"
FOR EACH ROW
WHEN (NEW.test_lead_id in ('150','151'))
BEGIN
IF :new.test_id = '1000' then
:new.test_id := '2000';
END IF;
END;
Or
CREATE OR REPLACE TRIGGER test_trigger
BEFORE INSERT ON "test_list"
FOR EACH ROW
WHEN (NEW.test_lead_id in ('150','151') and new.test_id = '1000')
BEGIN
:new.test_id := '2000';
END;

Something like this?
CREATE OR REPLACE TRIGGER test_trigger
BEFORE INSERT
ON "test_list"
FOR EACH ROW
BEGIN
IF :new.text_lead_id IN ('150', '151')
AND :old.test_id = '1000'
THEN
:new.text_id := '2000';
END IF;
END;

Related

How to prevent trigger from updating the timestamp on a column in Oracle?

I have a table which has a column on which I have set a trigger to update the timestamp when there is an update on the row
CREATE TABLE mytable (
id NUMBER NOT NULL,
sid VARCHAR(10) NOT NULL,
stext VARCHAR(10),
tid VARCHAR(10),
ttext VARCHAR(10),
last_updated TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
CONSTRAINT unique PRIMARY KEY (id) ENABLE
);
CREATE OR REPLACE trigger last_updated_trigger
BEFORE UPDATE ON mytable
FOR EACH ROW
BEGIN
select systimestamp into :new.last_updated from dual;
END;
/
However, when certain SQLs are executed on the table, I do NOT want the 'last_updated' column to be updated. For instance, when the below SQL updates this table, I do NOT want the trigger to kick in. I need the column to retain the last_updated value so that my other queries do not get messed up. However, when other SQLs do updates on the data, I want the column to be updated.
Any ideas on how this could be done?
MERGE INTO mytable
USING dual
ON (id = ?)
WHEN MATCHED THEN
UPDATE SET
stext = case when sid = ? then ? else stext end,
ttext = case when tid = ? then ? else ttext end
You can easily keep a supplied value and only insert the current time if it is not supplied:
CREATE OR REPLACE trigger last_updated_trigger
BEFORE UPDATE ON mytable
FOR EACH ROW
BEGIN
:new.last_updated := coalesce(:new.last_updated, systimestamp);
END;
If you do not want to fire trigger when you update STEXT or TTEXT columns please try this:
CREATE OR REPLACE trigger last_updated_trigger
BEFORE UPDATE ON mytable
FOR EACH ROW
BEGIN
if (not updating('stext') and not updating('ttext')) then
:new.last_updated := systimestamp;
end if;
END;
Thanks
You can put that specific SQL Statement into a PROCEDURE in which the module info is updated for the concerned application(always call this statement from this procedure only) such as
CREATE OR REPLACE PROCEDURE Merge_Text AS
BEGIN
DBMS_APPLICATION_INFO.SET_MODULE($$plsql_unit,null);
MERGE INTO mytable
USING dual
ON (id = ?)
WHEN MATCHED THEN
UPDATE SET
stext = case when sid = ? then ? else stext end,
ttext = case when tid = ? then ? else ttext end;
END;
/
and then distinguish this caller module within the trigger such as
CREATE OR REPLACE trigger last_updated_trigger
BEFORE UPDATE ON mytable
FOR EACH ROW
v_module VARCHAR2(80);
v_action VARCHAR2(80);
BEGIN
DBMS_APPLICATION_INFO.READ_MODULE(v_module, v_action);
IF v_module != 'MERGE_TEXT' THEN
:new.last_updated := systimestamp;
END IF;
END;
/

Create Trigger to display message “Restock- <item-name>”, when a item quantity reaches 10 and below while updating or inserting item

table
Stock:
ITEMID NUMBER PRIMARY KEY
DESCRIPTION VARCHAR2(30)
QUANTITY NUMBER
CREATE OR REPLACE TRIGGER trig_1 BEFORE
UPDATE OR INSERT ON stock
FOR EACH ROW
DECLARE
v_des VARCHAR2(30);
v_quan NUMBER;
BEGIN
SELECT
quantity,
description
INTO
v_quan,
v_des
FROM
stock;
IF v_quan <= 10 THEN
dbms_output.put_line('Restock' || v_des);
END IF;
END;
You need to use :NEW cursor to refer to the new value that is being inserted or updated as following:
CREATE OR REPLACE TRIGGER TRIG_1 BEFORE
UPDATE OR INSERT ON STOCK
FOR EACH ROW
BEGIN
IF :NEW.QUANTITY <= 10 THEN
DBMS_OUTPUT.PUT_LINE('Restock - ' || :NEW.DESCRIPTION);
END IF;
END;
/
Make sure that you SET SERVEROUTPUT ON while inserting/updating the table data so that it is displayed in the output.
Cheers!!

Oracle Compound Trigger Mutation Table

I'm trying to create a compound trigger to avoid the mutation problem.
I've a table and a python's procedure that perfoms a transaction insert. The table has n fields.
What I´m trying to do is when a value of one of those fields is negative, then do not perform the operation , and insert the value from the previous record of the field (prior to insert) of the table. Another concern is that one of the fields is and id, to distinguish between sites.
For no, this is the code I've, Considering only one field (KWHGEN):
CREATE OR REPLACE TRIGGER "CIRCU3".D_measures_TP_test
--FOR INSERT OR UPDATE ON T_MEASURES_TP_NEW
FOR INSERT ON T_MEASURES_TP_NEW
COMPOUND TRIGGER
VAL_KWHGEN NUMBER(21,2);
VAL_autoin NUMBER (19,0);
AFTER EACH ROW IS
BEGIN
SELECT autoin, KWHGEN INTO VAL_ID_MED, VAL_KWHGEN FROM
(SELECT *
FROM T_measures_TP_NEW WHERE ID_site = :NEW.ID_site
ORDER BY TIMESTAMP DESC)
WHERE ROWNUM = 1;
IF :NEW.KWHGEN <0
THEN UPDATE T_MEASURES_TP_NEW SET KWHGEN = VAL_KWHGEN WHERE autoin = VAL_autoin;
END IF;
END AFTER EACH ROW;
END D_MEASURES_TP_test;
But the mutation error is following me ;-)
You have created trigger on T_MEASURES_TP_NEW and then updating same table T_MEASURES_TP_NEW within trigger. This will again call your trigger.
If the first select in trigger again returns negative value in VAL_KWHGEN then mutating error will follow you.
You defined only an AFTER EACH block, nothing else. This is the same as creating a row-level trigger (i.e. using FOR EACH ROW)
It must be like this (not tested):
CREATE OR REPLACE TRIGGER "CIRCU3".D_measures_TP_test
FOR INSERT ON T_MEASURES_TP_NEW
COMPOUND TRIGGER
VAL_KWHGEN NUMBER(21,2);
VAL_autoin NUMBER (19,0);
TYPE RowIdTableType IS TABLE OF ROWID;
TYPE KWHGENTableType IS TABLE OF T_MEASURES_TP_NEW.KWHGEN%TYPE;
RowIdTable RowIdTableType;
KWHGENTable KWHGENTableType;
BEFORE STATEMENT IS
BEGIN
RowIdTable := RowIdTable();
KWHGENTable := KWHGENTableType();
END BEFORE STATEMENT;
BEFORE EACH ROW IS
BEGIN
RowIdTable.EXTEND;
RowIdTable(RowIdTable.LAST) := :NEW.ROWID;
KWHGENTable.EXTEND;
KWHGENTable(RowIdTable.LAST) := :NEW.KWHGEN;
END BEFORE EACH ROW;
AFTER STATEMENT IS
BEGIN
FOR i IN RowIdTable.FIRST..RowIdTable.LAST LOOP
SELECT
DISTINCT MIN(autoin) OVER (ORDER BY TIMESTAMP DESC),
DISTINCT MIN(KWHGEN) OVER (ORDER BY TIMESTAMP DESC)
INTO VAL_ID_MED, VAL_KWHGEN
FROM T_measures_TP_NEW
WHERE ROWID = RowIdTable(i);
IF KWHGENTable(i) < 0
THEN UPDATE T_MEASURES_TP_NEW
SET KWHGEN = VAL_KWHGEN
WHERE autoin = VAL_autoin;
END IF;
END LOOP;
END AFTER STATEMENT;
END;
/
OK, I do have a solution:
1.- Create a package where record the new insert data (BEFORE)
create or replace PACKAGE PCK_MEDIDAS_TP AS
TYPE DATOS_MEDIDAS_TP IS RECORD(
v_id_sede NUMBER (10,0),
v_id_med NUMBER (10,0),
v_kwhGEN NUMBER (21,2),
v_timestamp TIMESTAMP
);
type T_MEDTP is table of DATOS_MEDIDAS_TP index by binary_integer;
tabla_medidas_tp T_MEDTP;
END PCK_MEDIDAS_TP;
2.- Create a procedure each row (BEFORE) to read the new insert data and then record them into de package's table.
create or replace TRIGGER "CIRCU3".D_MEDIDAS_TP_test
BEFORE INSERT ON T_MEDIDAS_TP_NEW
FOR EACH ROW
DECLARE
Indice binary_integer;
BEGIN
--AUTOINCREMENTAL DEL CAMPO ID_MEDIDAS
SELECT T_MEDIDAS_TP_NEW_SEQ.NEXTVAL INTO :NEW.id_MEDIDAS_OLD FROM DUAL;
Indice:= PCK_MEDIDAS_TP.tabla_medidas_tp.COUNT+1;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_sede := :NEW.ID_SEDE;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_med := :NEW.ID_MEDIDAS;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_kwhGEN := :NEW.KWHGEN;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_timestamp := :NEW.TIMESTAMP;
IF :NEW.KWHGEN <0 THEN
DBMS_OUTPUT.put_line('first trigger:' ||:NEW.ID_MEDIDAS||','||:NEW.ID_SEDE||','||:NEW.TIMESTAMP);
-- INSERT INTO TEST_TRIGGER VALUES ('100', :NEW.KWHGEN, SYSDATE);
--ELSE DBMS_OUTPUT.PUT_LINE('¿?');
END IF;
END;
3.- Create a statement procedure (AFTER) where you can check your condition, in my case if kwhgen <0. If is true, I'll read the previous record in the original tbale and update the insert record with taht value.
create or replace TRIGGER D_MEDIDAS_TP_TEST_STATEMENT
AFTER INSERT ON T_MEDIDAS_TP_NEW
DECLARE
Indice binary_integer;
s_id_sede NUMBER (10,0);
s_id_med NUMBER (10,0);
s_kwhGEN NUMBER (21,2);
s_timestamp TIMESTAMP;
BEGIN
FOR Indice in 1..PCK_MEDIDAS_TP.tabla_medidas_tp.count LOOP
DBMS_OUTPUT.put_line('second trigger: kwhgen: '||PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_kwhGEN||', id_sede: '||PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_sede);
IF PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_kwhGEN <0 THEN
DBMS_OUTPUT.put_line('second trigger: v_kwhGEN is negative');
SELECT prev_KWHGEN INTO s_kwhgen
from(
SELECT LEAD (KWHGEN,1) over (ORDER BY id_medidas desc) as prev_KWHGEN
FROM T_MEDIDAS_TP_NEW WHERE ID_SEDE = PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_sede
ORDER BY id_medidas DESC) where rownum =1;
INSERT INTO TEST_TRIGGER VALUES ('100', '5555', SYSDATE);
DBMS_OUTPUT.put_line('second trigger. KWHGEN: '||s_kwhGEN);
DBMS_OUTPUT.put_line('UPDATE');
UPDATE T_MEDIDAS_TP_NEW SET KWHGEN = S_KWHGEN WHERE ID_MEDIDAS = PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_med;
else DBMS_OUTPUT.put_line('¿?');
END IF;
END LOOP;
PCK_MEDIDAS_TP.tabla_medidas_tp.delete; -- vaciamos la tabla
END;

How to get number of rows affected by a statement when inside that statement's trigger

I have a statement level trigger that fires whenever INSERT UPDATE or DELETE operations are performed on a table (called customers). I want to display a message (to DBMS_OUTPUT) containing the number of rows that were inserted/updated/deleted.
I just want one message for each triggering statement, eg
'4 rows were inserted into customers table'.
How can I access the number of rows that are affected by the triggering statement from INSIDE the trigger declaration, ie XXX in the code below:
CREATE OR REPLACE TRIGGER customer_changes_trigger_2
AFTER INSERT OR UPDATE OR DELETE ON customers
DECLARE
v_operation VARCHAR(10);
v_number_rows NUMBER;
BEGIN
v_number := XXX;
IF INSERTING THEN
v_operation := 'inserted';
END IF;
IF UPDATING THEN
v_operation := 'updated';
END IF;
IF DELETING THEN
v_operation := 'deleted';
END IF;
DBMS_OUTPUT.PUT_LINE
(v_number_rows|| ' rows were ' || v_operation || ' from customers.');
END;
Can't find anything in the documentation, any help appreciated!
One way is to use a global variable to track the number of rows as there is no other way to get the row count from a statement level trigger. You would then need three triggers... one statement level to initialise the variable before the statement is run, one row level to add one to the variable for each row, one statement level to use the row count however you wish. First, set up the variable and a few procedures to help it:
create or replace package PKG_ROWCOUNT is
NUMROWS number;
procedure INIT_ROWCOUNT;
procedure ADD_ONE;
function GET_ROWCOUNT
return number;
end PKG_ROWCOUNT;
/
create or replace package body PKG_ROWCOUNT as
procedure INIT_ROWCOUNT is
begin
NUMROWS := 0;
end;
procedure ADD_ONE is
begin
NUMROWS := Nvl(NUMROWS, 0) + 1;
end;
function GET_ROWCOUNT
return number is
begin
return NUMROWS;
end;
end PKG_ROWCOUNT;
/
The first trigger to initialise the variable:
create or replace trigger CUSTOMER_CHANGES_TRIGGER_1
before insert or update or delete
on CUSTOMERS
begin
PKG_ROWCOUNT.INIT_ROWCOUNT;
end;
The second to update per row:
create or replace trigger CUSTOMER_CHANGES_TRIGGER_2
after insert or update or delete
on CUSTOMERS
for each row
begin
PKG_ROWCOUNT.ADD_ONE;
end;
/
The third to display the total:
create or replace trigger CUSTOMER_CHANGES_TRIGGER_3
after insert or update or delete
on CUSTOMERS
begin
Dbms_output.
PUT_LINE(PKG_ROWCOUNT.GET_ROWCOUNT || ' rows were affected.');
end;
I'm not 100$ sure if it's available inside AFTER trigger body, but you can try examining sql%rowcount

How to set new date entries to current date?

I am trying to create a trigger. It is supposed to update any new date entry to sysdate. So far, I have the following code. However, I get "invalid table name" and "SQL statement ignored" errors.
CREATE OR REPLACE TRIGGER new_orders
AFTER INSERT ON orders
FOR EACH ROW
BEGIN
IF INSERTING THEN
UPDATE
SET order_date := SYSDATE;
END IF;
END;
/
CREATE OR REPLACE TRIGGER new_orders
BEFORE INSERT ON orders
FOR EACH ROW
BEGIN
:NEW.order_date := SYSDATE;
END;
/

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