Is it possible to reference a second table within a trigger?
create or replace trigger table1
before update of status_code on table1
for each row
declare z_user_id table2.user_id;
begin
if :new.status_code in (30,40) then
:new.z_open_01 := nvl(:OLD.z_user_id, nvl(:NEW.z_user_id, :old.z_open_01));
end if;
end;
/
As to your question: Yes.
The :old and :new constructs only apply to the table that cause the trigger to fire.
The way you have that written you are triggering off of Table1, but your description sounds like you want to grab a value from table one when something in Table2 changes.
But you didn't say what you want to DO with the userid you grab.
If you create a trigger on Table2, read a value from Table1, and save the value in a column in the row that fired the trigger you are gtg. Other scenarios get more complex.
so, based on comments something like:
create or replace trigger table2
after update of status_code on table2
for each row when (:new.status_code in (30,40))
declare t1_user Table1.user_id%type;
begin
Select user_id into t1_user from Table1 where <condition>
:new.z_open_01 := t1_user;
end if;
end;
/
setting up whatever condition select the desired user from Table1.
Related
As discussed here, I'm unable to use :OLD and :NEW on columns with collation other than USING_NLS_COMP. I'm trying to find a way around this but haven't been successful so far.
This is the original trigger:
CREATE OR REPLACE TRIGGER SYS$PERSONSSALUTATIONAU
AFTER UPDATE ON PERSONS
FOR EACH ROW
begin
State_00.Salutations_ToDelete(State_00.Salutations_ToDelete.Count + 1) := :old.SalutationTitle;
State_00.Salutations_ToInsert(State_00.Salutations_ToInsert.Count + 1) := :new.SalutationTitle;
end;
This is what I've tried:
CREATE OR REPLACE TRIGGER SYS$PERSONSSALUTATIONAU
FOR UPDATE ON Persons
COMPOUND TRIGGER
TYPE Persons_Record IS RECORD (
SalutationTitle NVARCHAR2(30)
);
TYPE Persons_Table IS TABLE OF Persons_Record INDEX BY PLS_INTEGER;
gOLD Persons_Table;
gNEW Persons_Table;
BEFORE EACH ROW IS BEGIN
SELECT SalutationTitle
BULK COLLECT INTO gOLD
FROM Persons
WHERE ID = :OLD.ID;
END BEFORE EACH ROW;
AFTER EACH ROW IS BEGIN
SELECT SalutationTitle
BULK COLLECT INTO gNEW
FROM Persons
WHERE ID = :NEW.ID;
END AFTER EACH ROW;
AFTER STATEMENT IS BEGIN
FOR i IN 1 .. gNEW.COUNT LOOP
State_00.Salutations_ToDelete(State_00.Salutations_ToDelete.Count + 1) := gOLD(i).SalutationTitle;
State_00.Salutations_ToInsert(State_00.Salutations_ToInsert.Count + 1) := gNEW(i).SalutationTitle;
END LOOP;
END AFTER STATEMENT;
END;
This results in error ORA-04091. I've also tried moving the select into the AFTER STATEMENT section which works, but there is no way to access the old values. If somebody has a solution for this it would be most appreciated.
EDIT:
I created a minimal reproducible example:
CREATE TABLE example_table (
id VARCHAR2(10),
name NVARCHAR2(100)
);
CREATE TABLE log_table (
id VARCHAR2(10),
new_name NVARCHAR2(100),
old_name NVARCHAR2(100)
);
CREATE OR REPLACE TRIGGER example_trigger
AFTER UPDATE ON example_table
FOR EACH ROW BEGIN
INSERT INTO log_table VALUES(:old.id, :new.name, :old.name);
END;
INSERT INTO example_table VALUES('01', 'Daniel');
-- this works as expected
UPDATE example_table SET name = ' John' WHERE id = '01';
SELECT * FROM log_table;
DROP TABLE example_table;
CREATE TABLE example_table (
id VARCHAR2(10),
-- this is the problematic part
name NVARCHAR2(100) COLLATE XCZECH_PUNCTUATION_CI
);
INSERT INTO example_table VALUES('01', 'Daniel');
-- here nothing is inserted into log_example, if you try to
-- recompile the trigger you'll get error PLS-00049
UPDATE example_table SET name = ' John' WHERE id = '01';
SELECT * FROM log_table;
DROP TABLE example_table;
DROP TABLE log_table;
DROP TRIGGER example_trigger;
In the discussion you reference a document concerning USING_NLS_COMP. That has nothing to do with the error you are getting. The error ORA-04091 is a reference to the table that fired the trigger (mutating). More to come on this. I am not saying you do not have USING_NLS_COMP issues, just that they are NOT causing the current error.
There are misconceptions shown in your trigger. Beginning with the name itself; you should avoid the prefix SYS. This prefix is used by Oracle for internal objects. While SYS prefix is not specifically prohibited at best it causes confusion. If this is actually created in the SYS schema then that in itself is a problem. Never use SYS schema for anything.
There is no reason to create a record type containing a single variable, then create a collection of that type, and finally define variables of the collection. Just create a collection to the variable directly, and define variables of the collection.
The bulk collect in the select statements is apparently misunderstood as used. I assume you want to collect all the new and old values in the collections. Bulk collect however will not do this. Each time bulk collect runs the collection used is cleared and repopulated. Result being the collection contains only the only the LAST population. Assuming id is unique the each collection would contain only 1 record. And now that brings us to the heart of the problem.
The error ORA-04091: <table name> is mutating, trigger/function may not see it results from attempting to SELECT from the table that fired the trigger; this is invalid. In this case the trigger fired due to a DML action on the persons table as a result you cannot select from persons in a row level trigger (stand alone or row level part of a compound trigger. But it is not needed. The pseudo rows :old and :new contain the complete image of the row. To get a value just reference the appropriate row and column name. Assign that to your collection.
Taking all into account we arrive at:
create or replace trigger personssalutation
for update
on persons
compound trigger
type persons_table is table of
persons.salutationtitle%type;
gold persons_table := persons_table();
gnew persons_table := persons_table();
before each row is
begin
gold.extend;
gold(gold.count) := :old.salutationtitle;
end before each row;
after each row is
begin
gnew.extend;
gold(gold.count) := :new.salutationtitle;
end after each row;
after statement is
begin
for i in 1 .. gnew.count loop
state_00.salutations_todelete(state_00.salutations_todelete.count + 1) := gold(i);
state_00.salutations_toinsert(state_00.salutations_toinsert.count + 1) := gnew(i);
end loop;
end after statement;
end personssalutation;
NOTE: Unfortunately you did not provide sample data, nor description of the functions in the AFTER STATEMENT section. Therefore the above is not tested.
I have a problem with a "after insert" trigger which won't pass the value to a stored procedure that i'm calling inside the trigger.
It works ok for update and also i should mention that i am querying the table in the procedure that i am calling.
It goes something like:
create or replace trigger test_trg
after insert or update on table1
for each row
begin
test_procedure(:new.value1);
end;
The procedure looks inside table1 and inserts in table2 hints about what should be added in table1 based on the current inserted/updated row.
Thanks in advance!!
I found it!
The problem was not the trigger, it was in the procedure. I was performing a "dirty read" based on the record ID that i was sending (the record id of a new row).
Even though my trigger is "after insert" it looks like my row can't be found by the procedure and i was basing all my operations on it.
Fixed it by adding more parameters to the procedure and passing :new values straight from the trigger for everything i needed.
A trigger transaction is depend on its statement transaction. Therefore you can not read uncommitted records. So you should transfer "test_procedure" codes into your trigger and use :New record values to insert data into table2.
Your code should look like this:
create or replace trigger test_trg
after insert or update on table1
for each row
begin
if inserting then
insert into table2(ID, F1, F2, ...)
values (NEW_ID_VALUE, :NEW.F1_VALUE, :NEW.F2_VALUE, ...);
elsif updating then
update table2
set F1 = :NEW.F1_VALUE
, F2 = :NEW.F2_VALUE
where TABLE1_ID_FK = :NEW.ID;
end if;
end;
So I am trying to add age with price and store the result on another table with the ID of the person who did this. I am able to set the business rule by making the trigger but when I check my second (END) table, there is nothing there.. Here is my code for the trigger:
CREATE OR REPLACE TRIGGER JIM
BEFORE INSERT ON END
FOR EACH ROW ENABLE
DECLARE
V_AGE JIM.AGE%TYPE;
V_PRICE JIM.PRICE%TYPE;
v_prices NUMBER(20);
BEGIN
SELECT AGE,PRICE INTO V_AGE,V_PRICE FROM JIM WHERE ID=:NEW.ID;
v_prices:=V_AGE+V_PRICE;
INSERT INTO END VALUES(:new.ID,v_prices);
END;
However, When I insert values onto the JIM table using the following code:
insert into jim values(4,'Sim',45,100);
nothing actually gets stored on the END table. i am sort of new to triggers and its so confusing. Please let me know what to do. thanls
Don't use a keyword end as a table name, this causes problem during
creation of trigger. I've presumed the table's name as t_end.
I think you are confused on which table to define trigger. It seems
you should define on table jim instead of t_end.
I've presumed you have a sequence named seq_end to populate the id
column of the table t_end
So , your trigger creation statement will be as follows :
create or replace trigger trg_ins_jim before insert on jim for each row
declare
v_id_end t_end.id%type;
v_prices t_end.prices%type;
begin
v_prices := :new.age + :new.price;
v_id_end := seq_end.nextval; insert into t_end values(v_id_end, v_prices);
/* if you have defined sequence for t_end as default value of id column, you may change the upper row as "insert into t_end(prices) values(v_prices);" and there would be no need for "v_id_end" */
end;
and when you issue insert into jim values(4,'Sim',45,100); command, you'll also have values inserted into t_end.
If there is only one table, then the SELECT and the INSERT are redundant.
CREATE OR REPLACE TRIGGER trigger_name
BEFORE INSERT ON table_name
FOR EACH ROW
BEGIN
:NEW.PRICES := :NEW.AGE + :NEW.PRICE;
END;
Possible duplicate
The question I am going to ask is already there. But I don't have answer for this.
Please refer the below link.
ORACLE TRIGGER INSERT INTO ... (SELECT * ...)
I have around 600 columns in a table. After each insert in this table I need to insert the new row in another backup table.
Please tell how to use "INSERT INTO TABLE_NAME2 SELECT * FROM TABLE_NAME1" query in trigger.
Note: Without specifying columns in insert or select clause
Structure of both table is same. Specifying all the column name in trigger is difficult and also if new columns added, we need to add in trigger as well.
SQL> CREATE or REPLACE TRIGGER emp_after_insert AFTER INSERT ON emp
FOR EACH ROW
DECLARE
BEGIN
insert into emp_backup values (:new.empid, :new.fname, :new.lname);
DBMS_OUTPUT.PUT_LINE('Record successfully inserted into emp_backup table');
END;
reference:
http://www.tech-recipes.com/rx/19839/oracle-using-the-after-insert-and-after-update-triggers/
You should use COMPOUND TRIGGER. This trigger should look like this:
CREATE OR REPLACE TRIGGER t_copy_table1
FOR INSERT ON table1
COMPOUND TRIGGER
v_id number;
BEFORE EACH ROW IS
BEGIN
v_id := :new.id;
END BEFORE EACH ROW;
AFTER STATEMENT IS
BEGIN
insert into table2 select * from table1 where id=v_id;
END AFTER STATEMENT;
END t_copy_table1;
I have some problem executing the trigger below:
CREATE OR REPLACE TRIGGER AFTERINSERTCREATEBILL
AFTER INSERT
ON READING
FOR EACH ROW
DECLARE
varReadNo Int;
varMeterID Int;
varCustID Varchar(10);
BEGIN
SELECT SeqReadNo.CurrVal INTO varReadNo FROM DUAL;
Select MeterID INTO varMeterID
From Reading
Where ReadNo = varReadNo;
Select CustID INTO varCustID
From Address A
Join Meter M
on A.postCode = M.postCode
Where M.MeterID = varMeterID;
INSERT INTO BILL VALUES
(SEQBILLNO.NEXTVAL, SYSDATE, 'UNPAID' , 100 , varCustID , SEQREADNO.CURRVAL);
END;
Error Message:
*Cause: A trigger (or a user defined plsql function that is referenced in
this statement) attempted to look at (or modify) a table that was
in the middle of being modified by the statement which fired it.
*Action: Rewrite the trigger (or function) so it does not read that table.
Does it mean that I am not suppose to retrieve any details from table Reading?
I believe that the issue occur as I retrieving data from Table Reading while it is inserting the value:
SELECT SeqReadNo.CurrVal INTO varReadNo FROM DUAL;
Select MeterID INTO varMeterID
From Reading
Where ReadNo = varReadNo;
It's there anyway to resolve this? Or is there a better method to do this? I need to insert a new row into table BILL after entering the table Reading where the ReadNo need to reference to the ReadNo I just insert.
You cannot retrieve records from the same table in a row trigger. You can access values from actual record using :new and :old (is this your case?). The trigger could then be rewritten to
CREATE OR REPLACE TRIGGER AFTERINSERTCREATEBILL
AFTER INSERT
ON READING
FOR EACH ROW
DECLARE
varCustID Varchar(10);
BEGIN
Select CustID INTO varCustID
From Address A
Join Meter M
on A.postCode = M.postCode
Where M.MeterID = :new.MeterID;
INSERT INTO BILL VALUES
(SEQBILLNO.NEXTVAL, SYSDATE, 'UNPAID' , 100 , varCustID , SEQREADNO.CURRVAL);
END;
If you need to query other record from READING table you have to use a combination of statement triggers, row trigger and a PLSQL collection. Good example of this is on AskTom.oracle.com
Make sure that you have the necessary permissions on all the tables and access to the sequences you're using in the insert.
I haven't done Oracle in awhile, but you can also try querying dba_errors (or all_errors) in order to try and get more information on why your SP isn't compiling.
Something to the tune of:
SELECT * FROM dba_errors WHERE owner = 'THEOWNER_OF_YOUR_SP';
Add exception handling in your trigger and see what is happening, by doing it would be easy for you to track the exceptions.
CREATE OR REPLACE TRIGGER AFTERINSERTCREATEBILL
AFTER INSERT
ON READING
FOR EACH ROW
DECLARE
varCustID Varchar(10);
BEGIN
-- your code
EXCEPTION
WHEN NO_DATA_FOUND
THEN
DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQLERRM(-20299)));
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQLERRM(-20298)));
END;
we can combined insert and select statement
CREATE OR REPLACE TRIGGER AFTERINSERTCREATEBILL
AFTER INSERT
ON READING
FOR EACH ROW
DECLARE
varCustID Varchar(10);
BEGIN
insert into bill
values
select SEQBILLNO.NEXTVAL,
SYSDATE,
'UNPAID' ,
100 ,
CustID,SEQREADNO.CURRVAL
From Address A
Join Meter M
on A.postCode = M.postCode
Where M.MeterID = :new.MeterID;
END;
try the above code.