What I would like to do is;
after I insert some data into table1, I would like some of that data automatically inserted into table2, such as the primary key from table1 inserted into table2 as a foreign key.
Is this done using a trigger.
Not sure where to start looking first.
Cheers
Brian
Yes you can do that through trigger. You can do it like this:
CREATE OR REPLACE TRIGGER my_trigger
before INSERT ON table1
REFERENCING NEW AS NEW
for each row
BEGIN
insert into table2(fk_column,column1) values(:new.pk_column_of_table1,'value1');
END;
you can create a trigger as #vance said and you can use returning into clause if you are populating some of the columns dynamically
INSERT INTO t1 VALUES (t1_seq.nextval, 'FOUR')
RETURNING id INTO l_id;
have a look here
Related
Good morning, I am trying to audit two tables, and I have investigated that it cannot be done, therefore I explain what I wanted to do:
I have two tables (Participante, Actividad) which are joined by a third table (Part_Actividad)
I want to audit the Participants table, but in the same way I need the Id of the activity to know in which activity the data of a participant is changed.
Ideas I had
Create a trigger like the following
CREATE OR REPLACE TRIGGER Tri_Auditoria
AFTER INSERT ON Participante
FOR EACH ROW
DECLARE
v_Participante_ID Participante.Participante_ID%TYPE;
v_Actividad_ID Part_Actividad.Actividad_ID%TYPE;
BEGIN
SELECT participante_ID INTO v_Participante_ID
FROM Participante;
SELECT Actividad_ID INTO v_Actividad_ID
FROM Part_Actividad
WHERE PartAct_ID = v_Participante_ID;
INSERT INTO Auditoria(Auditoria_ID, Actividad_ID, Participante_ID, TipPart_ID_Ant, Part_P_Nombre_Ant, Part_P_Apell_Ant, Part_Cedula_Ant, Part_Genero_ant, Part_FNaci_Ant, Aud_Operacion, Usuario_Modificador, Fecha_Modificacion)
VALUES (sec_Auditoria.nextval, v_Actividad_ID, :new.Participante_ID,:new.TipPart_ID,:new.Part_P_Nom,:new.Part_P_Apell,:new.Part_Cedula,:new.Part_Genero,:new.Part_FNaci,'I',USER,sysdate);
END Tri_Auditoria;
/
Result:
When I insert data into the participante table, it is not inserted and it sends a trigger error.
Mutating table error, isn't it? That's because you're selecting from the same table which caused trigger to fire, and that's not allowed.
Anyway, you shouldn't do that because you have that value in disposal - just reference it using the :new pseudorecord, such as
CREATE OR REPLACE TRIGGER Tri_Auditoria
AFTER INSERT ON Participante
FOR EACH ROW
DECLARE
v_Actividad_ID Part_Actividad.Actividad_ID%TYPE;
BEGIN
SELECT Actividad_ID
INTO v_Actividad_ID
FROM Part_Actividad
WHERE PartAct_ID = :new.participante_ID; --> this
INSERT INTO Auditoria
(Auditoria_ID, Actividad_ID, Participante_ID,
TipPart_ID_Ant, Part_P_Nombre_Ant, Part_P_Apell_Ant,
Part_Cedula_Ant, Part_Genero_ant, Part_FNaci_Ant,
Aud_Operacion, Usuario_Modificador, Fecha_Modificacion)
VALUES (sec_Auditoria.nextval, v_Actividad_ID, :new.Participante_ID,
:new.TipPart_ID,:new.Part_P_Nom,:new.Part_P_Apell,
:new.Part_Cedula,:new.Part_Genero,:new.Part_FNaci,
'I',USER,sysdate);
END Tri_Auditoria;
/
I need to write a trigger in Oracle PL/SQL (11g) before inserting each row that checks if a row exists: if it doesn't exists creates a new row, if it does exists updates the existing record.
Which is the best way to do that?
Thanks, Gianluca
What you want to do is a MERGE INTO:
MERGE INTO myTable t
USING (SELECT 'Smith' AS Name, 1 AS Id FROM DUAL) data -- put your data in here
ON (t.Id = data.Id) -- pk or other matching criteria
WHEN MATCHED
THEN
UPDATE SET t.name = data.name
WHEN NOT MATCHED
THEN
INSERT (Id, Name)
VALUES (data.Id, data.Name);
Buildiing a trigger is possible but no allowed/intended. You should't do this.
You'd try to abbort the insert and do something else. This is not a good idea, because of many thing: hidden logic in db, stupid-clients which are doing wrong things..
You can abort with an error, but it doesn't sound like you idea this way.
If you want to do it you could change to update. Never insert anything and implement a trigger before update, which checks if the row exists:
CREATE OR REPLACE TRIGGER myTableTrigger
BEFORE UPDATE
ON myTable
FOR EACH ROW
BEGIN
-- If row doesn't exist. Insert one before the update..
END;
Alternatively you could go the long way and build some views:
https://dba.stackexchange.com/questions/24047/oracle-abort-within-a-before-insert-trigger-without-throwing-an-exception
I have two table,and they are connected by one field : B_ID of table A & id of table B.
I want to use sql to insert data to this two table.
how to write the insert sql ?
1,id in table B is auto-increment.
2,in a stupid way,I can insert data to table B first,and then select the id from table B,then add the id to table A as message_id.
You cannot insert data to multiple tables in one SQL statement. Just insert data first to B table and then table A. You could use RETURNING statement to get ID value and get rid of additional select statement between inserts.
See: https://oracle-base.com/articles/misc/dml-returning-into-clause
Have you heard about AFTER INSERT trigger? I think it is what you are looking for.
Something like this might do what you want:
CREATE OR REPLACE TRIGGER TableB_after_insert
AFTER INSERT
ON TableB
FOR EACH ROW
DECLARE
v_id int;
BEGIN
/*
* 1. Select your id from TableB
* 2. Insert data to TableA
*/
END;
/
i want to insert from a type of table into a table.
Is there a way to do this with bulk? And can I change the type table content a little?
Just like here, but the other way around:
How to insert data into a PL/SQL table type rather than PL/SQL table?
Assuming that you have something like
CREATE TYPE my_nested_table_type
AS TABLE OF <<something>>;
DECLARE
l_nt my_nested_table_type;
BEGIN
<<something that populates l_nt>>
then the way to do a bulk insert of the data from the collection into a heap-organized table would be to use a FORALL
FORALL i in 1..l_nt.count
INSERT INTO some_table( <<list of columns>> )
VALUES( l_nt(i).col1, l_nt(i).col2, ... , l_nt(i).colN );
I'm looking for the best way to change a data type of a column in a populated table. Oracle only allows changing of data type in colums with null values.
My solution, so far, is a PLSQL statement which stores the data of the column to be modified in a collection, alters the table and then iterates over the collection, restoring the original data with data type converted.
-- Before: my_table ( id NUMBER, my_value VARCHAR2(255))
-- After: my_table (id NUMBER, my_value NUMBER)
DECLARE
TYPE record_type IS RECORD ( id NUMBER, my_value VARCHAR2(255));
TYPE nested_type IS TABLE OF record_type;
foo nested_type;
BEGIN
SELECT id, my_value BULK COLLECT INTO foo FROM my_table;
UPDATE my_table SET my_value = NULL;
EXECUTE IMMEDIATE 'ALTER TABLE my_table MODIFY my_value NUMBER';
FOR i IN foo.FIRST .. foo.LAST
LOOP
UPDATE my_table
SET = TO_NUMBER(foo(i).my_value)
WHERE my_table.id = foo(i).id;
END LOOP;
END;
/
I'm looking for a more experienced way to do that.
The solution is wrong. The alter table statement does an implicit commit. So the solution has the following problems:
You cannot rollback after alter the alter table statement and if the database crashes after the alter table statement you will loose data
Between the select and the update users can make changes to the data
Instead you should have a look at oracle online redefinition.
Your solution looks a bit dangerous to me. Loading the values into a collection and subsequently deleting them fom the table means that these values are now only available in memory. If something goes wrong they are lost.
The proper procedure is:
Add a column of the correct type to the table.
Copy the values to the new column.
Drop the old column.
Rename the new column to the old columns name.