You are an awesome comunity. It is the first time I couldn't find an answer for my questions and I had millions
Take me easy. I'm super noob and I already fell bad for making you waste your time with my dummy question
Soo... I'm tring to make an app with oracle apex. I have an form with an interactive report for table1. On the form page I have 3 processes in this order:
Automatic Row Processing (DML) that apex automaticaly made for me,
a pl/sql process I made and
the reset page process apex made.
The ARP updates, creates and deletes and is triggered by any of the buttons (SAVE, CREATE, DELETE).
My procces deletes a row in another table2 and is performed when DELETE is clicked and ITEM1 is not null (because in ITEM1 I stored the PK for the row in the second table).
The last process is the usual reset page that should clear all items value when DELETE is pressed.
Firing point is by default "Processing" for all 3.
Sometimes my process fails (and return the error I set) because of a FK constraint.
Now here is the think: If my proccess fails, the oder 2 seem not to be executed. Is that posible? If i set the condition (to be executed) of my process to Never the other 2 are working. What am I missing?
You aren't missing anything.
When you push a button that fires those processes, they make a transaction. If any of them raises an error, all of them (executed so far) are rolled back.
If you want to continue processing regardless what your own procedure (2nd one) does (I mean: whether it succeeds or not), then handle it, somehow.
A trivial (and not the best) option is to ignore possible errors, e.g.
begin
delete from child_table where id = :P1_ITEM1;
exception
when others then null; --> ignore any errors
end;
Smarter way would be to intercept errors you expect. If you know (and yes, you do) that there's a possibility that foreign key constraint will be violated, check whether child rows exist; if not, delete the master row.
declare
l_id child_table.id%type;
begin
-- If row(s) with such an ID exists, L_ID will be set to that value.
-- In that case, don't do anything
select m.id
into l_id
from child_table m
where m.id = :P1_ITEM1
and rownum = 1;
-- The above query returned something; don't do anything
null;
exception
when no_data_found then
-- The above query didn't return anything, so - delete a row
delete from child_table where id = :P1_ID;
end;
Now, that can/could/should be modified, depending on what you really have; it is just an idea what to look at.
Yet another option is to set foreign key constraint to be on delete cascade, which means that deleting master record automatically deletes its detail records. Doing so, you wouldn't care about such a problems and your 2nd process would be as simple as
delete from child_table where id = :P1_ID;
(unless you hit another kind of an error, of course).
If you want to let users decide whether they want to delete rows or not, change button's action to "Redirect to URL" (currently it is "Submit", I presume). The target URL will be something like this (suppose that button's name is P1_START_PROCESSES):
javascript:if(confirm('Are you sure you want to delete all rows related to this document?')){doSubmit('P1_START_PROCESSES');}
Related
I am developing an order transaction where a user can order a product. Once they clicked the 'add to cart' button, it will be able to save on the database in how many times they want with the same order id. Order id is like a transaction id.
My problem is that whenever I want to display the items that customer ordered, it displays an error or ORA 01422. How can I resolve this error?
Here is my code
DECLARE
order_item_id NUMBER;
BEGIN
order_item_id := :MOTOR_PRODUCTS_ORDER.M_ORDERID;
SELECT MOTOR_ID,
MOTOR_QTY_PURCHASED,
UNITPRICE
INTO :MOTOR_ORDER_ITEMS.MOTOR_ID,
:MOTOR_ORDER_ITEMS.MOTOR_QTY_PURCHASED,
:MOTOR_ORDER_ITEMS.UNITPRICE
FROM MOTOR_ORDERS
WHERE motor_order_id = order_item_id;
END;
As krokodilo says, this error is caused because your query returns multiple rows. Depending on what you want to do, you have a couple of options.
If you want multiple values then either use a loop and process them one row at a time (if you are going to be performing a dml operation use bulk collect). If you only want a single row then narrow your result set down with an extra where clause, or use MAX to ensure you only get one value back.
If there is more than one row which will be returned from a query you'll need to use a cursor. One way to do this is with a cursor FOR loop:
DECLARE
order_item_id NUMBER;
BEGIN
order_item_id := :MOTOR_PRODUCTS_ORDER.M_ORDERID;
FOR aRow IN (SELECT MOTOR_ID, MOTOR_QTY_PURCHASED, UNITPRICE
FROM MOTOR_ORDERS
WHERE motor_order_id = order_item_id)
LOOP
-- Do something here with the values in 'aRow'. For example, you
-- might print them out:
DBMS_OUTPUT.PUT_LINE('MOTOR_ID=' || aRow.MOTOR_ID ||
' MOTOR_QTY_PURCHASED=' || aRow.MOTOR_QTY_PURCHASED ||
' UNITPRICE=' || aRow.UNITPRICE);
END LOOP;
END;
Best of luck.
This looks like a Forms question; is it? If so, my suggestion is to let Forms do that job for you.
According to what you posted, there are two blocks:
MOTOR_PRODUCTS_ORDER (a master block, form type)
MOTOR_ORDER_ITEMS (a detail block, tabular type)
I guess that there is a master-detail relationship between them. If there's none, I'd suggest you to create it. Although you can make it work without such a relationship, it'll be much more difficult. If you are unsure of how to do it, start from scratch:
delete MOTOR_ORDER_ITEMS block (detail)
create it once again, this time by following the Data Block Wizard
Set MOTOR_PRODUCTS_ORDER to be its master block
Relationship is on ORDER_ID column/item
Let's presume that by this point everything is set up. Retrieving items that belong to that ORDER_ID is now very simple:
navigate to master block
enter query mode
enter value into an item that represents ORDER_ID
execute query
End of story. Forms triggers & procedures (which were created by the Wizard) will do its job and retrieve both master and detail records.
No need for additional coding; if you're skilled developer, you can create such a form in a matter of minutes. Won't be beautiful, but will be effective & reliable.
There's really no use in doing it manually, although it is possible. Your code works if there's a single item for that ORDER_ID. For two or more items, as you already know, it'll fail with TOO-MANY-ROWS error.
Basically, if you insist, you should use a loop:
you'd enter ORDER_ID into the master block
as you need to move through the detail block, i.e. use NEXT_RECORD, which is a restricted procedure, you can't use number of triggers (open Forms Online Help System and read about them) so a "Show items" button (with its WHEN-BUTTON-PRESSED trigger) might be just fine
a cursor FOR loop would be your choice
for every row it fetches, you'd populate block items and
navigate to next record (otherwise, you'd keep overwriting existing values in the 1st tabular block row)
As I said: possible, but not recommended.
So I am trying to use triggers to basically set some rules.. If anyone has an ID number lower than 3, he will have to pay only 100 dollars, but if someone has an ID above that, he will have to pay more. I did some research and have been told to use triggers and that triggers are very useful when fetching multiple rows. So I tried doing that but it didn't work. Basically the trigger gets created but then when i try to add values, I get the following error:-
ORA-01422: exact fetch returns more than requested number of rows
ORA-06512: at "S.PRICTICKET", line 6
ORA-04088: error during execution of trigger 'S.PRICTICKET'
here is what i did to make the trigger:-
CREATE OR REPLACE TRIGGER PRICTICKET BEFORE INSERT OR UPDATE OR DELETE ON PAYS FOR EACH ROW ENABLE
DECLARE
V_PRICE PAYS.PRICE%TYPE;
V_ID PAYS.ID%TYPE;
V_NAME PAYS.NAME%TYPE;
BEGIN
SELECT ID,NAME INTO V_ID,V_NAME FROM PAYS;
IF INSERTING AND V_ID<3 THEN
V_PRICE:=100;
INSERT INTO PAYS(ID,NAME,PRICE) VALUES (V_ID,V_NAME,V_PRICE);
ELSIF INSERTING AND V_ID>=3 THEN
V_PRICE:=130;
INSERT INTO PAYS(ID,NAME,PRICE) VALUES (V_ID,V_NAME,V_PRICE);
END IF;
END;
and the thing is, when i execute this code, i actually do get a message saying the trigger has been compiled. but when when i try to insert values into the table by using the following code, i get the error message I mentioned above.
INSERT INTO PAYS(ID,NAME) VALUES (19,'SS');
You're getting the error you specified, ORA-01422, because you're returning more than one row with the following SELECT:
SELECT ID,NAME INTO V_ID,V_NAME FROM PAYS;
You need to restrict the result set. For example, I'll use the :NEW psuedorecord to grab the row's new ID value, which if unique, will restrict the SELECT to one row:
SELECT ID,NAME INTO V_ID,V_NAME FROM PAYS WHERE ID = :NEW.ID;
Here is the Oracle docs on using triggers: https://docs.oracle.com/database/121/TDDDG/tdddg_triggers.htm#TDDDG99934
However, I believe your trigger has other issues, please see my comments and we can discuss.
EDIT: Based on our discussion.
ORA-04088: error during execution of trigger
Using INSERT inside a BEFORE INSERT trigger on the same table will create an infinite loop. Please consider using an AFTER INSERT and change your INSERTS to UPDATES, or an INSTEAD OF INSERT.
Additionally, remove DELETE from the trigger definition. That makes no sense in this context.
Let's begin clearing up a few things. You were told "triggers are very useful when fetching multiple rows" this is, as a general rule and without additional context, false. There are 4 types of DML triggers:
Before Statement - fires 1 time for the statement regardless of the number of rows processed.
Before Row - fires once for each row processed during the statement before old and new values are merged into a single set of values. At this point you are allowed to change the values in the columns.
After Row - fires once for row processed during the statement after merging old and new values into a single set of values. At this point you cannot change the column values.
After statement - fires once for the statement regardless of the number of rows processed.
Keep in mind that the trigger is effectively part of the statement.
A trigger can be fired for Insert, Update, or Delete. But, there is no need to fire on each. In this case as suggested, remove the Delete. But also the Update as your trigger is not doing anything with it. (NOTE: there are compound triggers, but they contain segments for each of the above).
In general a trigger cannot reference the table that it is fired upon. See error ORA-04091.
If you're firing a trigger on an Insert it cannot do an insert into that same table (also see ORA-04091) and even if you get around that the Insert would fire the trigger, creating a recursive and perhaps a never ending loop - that would happen here.
Use :New.column_name and :Old.column_name as appropriate to refer to column values. Do not attempt to select them.
Since you are attempting to determine the value of a column you must use a Before trigger.
So applying this to your trigger the result becomes:
CREATE OR REPLACE TRIGGER PRICTICKET
BEFORE INSERT ON PAYS
FOR EACH ROW ENABLE
BEGIN
if :new.id is not null
if :new.ID<3 then
:new.Price :=100;
else
:new.Price := 130;
end if ;
else
null; -- what should happen here?
end if ;
END PRICTICKET ;
is there any way to enable counting of rows that trigger modified in SQLite?
I know it is disabled https://www.sqlite.org/c3ref/changes.html and i understand why, but can i enable it somehow?
CREATE TABLE Users_data (
Id INTEGER PRIMARY KEY AUTOINCREMENT,
Deleted BOOLEAN DEFAULT (0),
Name STRING
);
CREATE VIEW Users AS
SELECT Id, Name
FROM Users_data
WHERE Deleted = 0;
CREATE TRIGGER UsersDelete2UsersData
INSTEAD OF DELETE
ON Users
FOR EACH ROW
BEGIN
UPDATE Users_data SET Deleted = 1 WHERE Id = OLD.Id;
END;
-- etc for insert & update
then delete from Users where Name like 'foo' /* doesnt even need 'Id = 1' */; works fine, but numbers of modified rows is, as documentation say, always zero.
(I cant modify my DAL to automatically add "where Deleted = 0", so backup plan is to have table Users_deleted and 'on delete' trigger on Users table without any view, but then i have to keep tracking FKs (for example, what to do when someone delete from FK table) and so on...)
Edit: Returned number is used for checking on database concurrency.
Edit2: To be more clear: As i say, I can not modify my DAL (Entity Framework 6), so the preferred answer should operate as follow pseudo code: int affectedRow = query("delete from Users where Name like 'foo';").Execute();
Its all about SQLite "trigger on view" behavior.
Use sqlite3_total_changes() instead:
This function returns the total number of rows inserted, modified or deleted by all INSERT, UPDATE or DELETE statements completed since the database connection was opened, including those executed as part of trigger programs.
Its imposible in sqlite3 (in 2015).
Basically I was looking for instead of trigger on view (as in question) with return function, which is not supported in sqlite.
By the way, postgresql (and i believe some others full db servers) can do it.
I have a table of people who belong to various sites. These sites can change, but don't very often. So when we create an attendance record (a learner_session object) we don't store the site. But this has cause a problem in reporting how many training hours a site has, because some people have changed sites over the years. Not by much, but we'd like to get this right.
So I've added a site_at_the_time column to the learner_session table. I want to auto-populate this with the site the person was at when they attended the session. But I'm not sure how to reference this. For some reason (I'm guessing to speed development or something) the learner_id is allowed to be null. So I'm currently planning to do an update trigger. The learner_id shouldn't ever get updated, and if it ever did somehow, the entire record would be junk so I'm not worried about it overwriting it.
The trigger I have now is
create trigger set_site_at_the_time
after update of learner_id on lrn_session
begin
:new.site_at_the_time:= (select site_id from learner who where :new.learner_id = who.learner_id);
end;
which leads me to the following error:
ORA-04082: NEW or OLD references not allowed in table level triggers
Now, I've done some research and found I need to use a FOR EACH ROW - and I'm wondering what exactly this FOR EACH ROW does - is it every row captured by the trigger? Or is it every row in the table?
Also, will this trigger when I create a record too? So if I do insert into learner_session(id,learner_id,...) values(learner_session_id_seq.nextval,1234,...) will this capture that appropriately?
And while I'm here, I might as well see if there's something else I'm doing wrong with this trigger. But I'm mainly asking to figure out what the FOR EACH ROW is supposed to do and if it triggers properly. =)
FOR EACH ROW means that the trigger will fire once for each row that is updated by your SQL statement. Without this clause, the trigger will only fire once, no matter how many rows are affected. If you want to change values as they're being inserted, you have to use FOR EACH ROW, because otherwise the trigger can't know which :new and :old values to use.
As written, the trigger only fires on update. To make it also fire upon insert, you'd need to change the definition:
CREATE TRIGGER set_site_at_the_time
BEFORE INSERT OR UPDATE OF learner_id
ON lrn_session
FOR EACH ROW
BEGIN
SELECT site_id into :new.site_at_the_time
FROM learner who
WHERE :new.learner_id = who.learner_id);
END set_site_at_the_time;
I googled this but, unfortunately, could not find any solution.
I have a simple form (Oracle Forms Builder 10g) with a single block. The form is written in Oracle EBS style, that is, the block is based on a view that fetches the base table fields together with the rowid and DML events (on-insert, on-update etc. triggers) are handled by a table handler package.
The functionality I wanted to add was the following: when a user creates a new record, the form automatically suggests values for all fields in the form. So, I created a WHEN-CREATE-RECORD trigger that calculates the field values and assigns them. All, except the primary key wich is based on a Sequence and is handled by the package.
Everything runs OK when I create the new record but when I attempt to save it, all I get is a FRM-40401 "no changes to save" error and nothing happens.
I tried to trace the error and it seems like the form considers the record as NEW with no changes on it. This happens even if I try to explicitly alter the record status to INSERT.
I already tried to change the default behaviour to STANDARD.COMMIT (created an ON-COMMIT trigger for that) but this did not dfix anything.
For the record, I tried to make the form table-based, getting rid of table handlers and leaving all DML to Forms. I still get FRM-40401.
I can't understand what is going wrong, any ideas please?
The record status is reset to NEW after the when-create-record trigger completes. This normally makes sense, since you are effectively setting the default values for items, but the user hasn't actually entered any data yet.
You need something to mark the record for insert after the trigger has finished - normally the user would do this when they enter some data into the record. If you want the user to be able to save the record without changing anything in it, you could perhaps add something to the save button to do a no-change assignment, e.g.
:MYBLOCK.ANYITEM := :MYBLOCK.ANYITEM;
This would cause the record to be marked for insert.
OK, for the time being I used the classic TIMER workaround and everything works as it should:
PACKAGE body form_timers IS
PROCEDURE CREATE_NEW_RECORD;
procedure do_create(name varchar2) is
timer_id TIMER;
Begin
timer_id := CREATE_TIMER(name,1,NO_REPEAT);
End;
procedure expired is
expired_timer CHAR(20);
BEGIN
expired_timer:=GET_APPLICATION_PROPERTY(TIMER_NAME);
IF expired_timer='CREATE_NEW_RECORD' THEN
CREATE_NEW_RECORD;
-- ELSIF expired_timer='T2' THEN
-- /* handle timer T2 */ NULL;
ELSE
NULL;
END IF;
END;
PROCEDURE CREATE_NEW_RECORD IS
/* create record logic goes here */
END;
END;
... but still, I'd like to know why this behaviour occurs.