So for now, I created 2 tables, Booking and BookingDetails, I want to create a trigger when I key in the details of BookingDetails it will automatically update totaldays inside the Booking table. Below is my code:
BookingDetails:
create table BookingDetail (
BD_ID int primary key not null,
Date_In date,
Date_Out date,
BK_ID int,
Room_ID int,
foreign key(BK_ID) references Booking(BK_ID),
foreign key(Room_ID) references Room(Room_ID)
)
And also Booking
create table Booking (
BK_ID int primary key not null,
BK_Date Date,
BK_TotalDays int,
BK_PayStatus char(6),
Cus_ID int,
Emp_ID int,
foreign key(Cus_ID) references customer(Cus_ID),
foreign key(Emp_ID) references Employee(Emp_ID)
)
With the function and trigger created:
create function countdays(t1 date, t2 date)
returns INT
return (timestampdiff(16, char(timestamp(t2) - timestamp(t1))))
create trigger totaldays
after insert on bookingdetail
referencing new as n
for each row mode db2sql
update booking
set bk_totaldays =
countdays((select date_in from bookingdetail), (select date_out from
bookingdetail))
where booking.bk_id = n.bk_id;
I have no problem executing these syntax, but when I try to input a new record inside Booking Detail to let the trigger triggers in Booking, errors occured, may I ask why? Thanks in advance.
Look at the information provided by the SQL error:
db2 ? SQL0811
SQL0811N The result of a scalar fullselect, SELECT INTO statement, or
VALUES INTO statement is more than one row.
So this part of your trigger expressions returns more than 1 row
set bk_totaldays = countdays((select date_in from bookingdetail),
(select date_out from bookingdetail))
Fix this to return a single row.
#MichaleTiefenbacher is correct about the cause of the error, but he's wrong about what to do about it. Let's take another look at your trigger again:
create trigger totaldays
after insert on bookingdetail
referencing new as n -- wait, what's this?
for each row mode db2sql
update booking
set bk_totaldays =
countdays((select date_in from bookingdetail), (select date_out from bookingdetail))
where booking.bk_id = n.bk_id;
You have a reference to the value you just inserted! When using FOR EACH ROW, the table reference NEW refers to the singular row just inserted. So you don't even need to look at the full table, just use what you just worked with:
create trigger totaldays
after insert on bookingdetail
referencing new as n
for each row mode db2sql
update booking
set bk_totaldays = countdays(n.date_in, n.date_out)
where booking.bk_id = n.bk_id;
(As I mentioned in my comment to your question, you'll likely want to change how you calculate the days, but that's irrelevant for this)
Related
How can I create a trigger to increase a date data from my table with each next row? I had an attempt, is below the table
What I want to do is to increase date from training_date_end by 1 week. But I don't know how to do it, just studying. Can anyone help?
CREATE TABLE training
(
coach_id int NOT NULL,
customer_id int NOT NULL,
training_date_start date NULL,
training_date_end date NULL,
training_place_id int NOT NULL,
CONSTRAINT training_pk PRIMARY KEY (training_place_id)
);
create or replace trigger lucky_week
before insert or update on training
for each row
begin
update training
set training_date_end = :new.training_date_end + 7
where training_date_end = :new.training_date_end;
end;
Most probably like this:
create or replace trigger lucky_week
before insert or update on training
for each row
begin
:new.training_date_end := :new.training_date_end + 7;
end;
Because, your trigger will suffer from the mutating table error (if you insert more than a single row), and - won't do anything in that case (because row you'd like to update doesn't exist yet).
In an Oracle Database, I need to create some trigger or procedure to treat this case in the most performative way possible (is an extremely large amount of data).
I have a table called ORDER_A that every day receives a full load (its truncated, and all records are inserted again).
I have a table called ORDER_B which is a copy of ORDER_A, containing the same data and some additional control dates.
Each insertion on ORDER_A must trigger a process that looks for a record with the same identifier (primary key: order_id) in table B.
If a record exists with the same order_id, and any of the other columns have changed, an update must be performed on table B
If a record exists with the same order_id, and no values in the other columns have been modified, nothing should be performed, the record must remain the same in table B.
If there is no record with the same order_id, it must be inserted in table B.
My tables are like this
CREATE TABLE ORDER_A
(
ORDER_ID NUMBER NOT NULL,
ORDER_CODE VARCHAR2(50),
ORDER_STATUS VARCHAR2(20),
ORDER_USER_ID NUMBER,
ORDER_DATE TIMESTAMP(6),
PRIMARY KEY (ORDER_ID)
);
CREATE TABLE ORDER_B
(
ORDER_ID NUMBER NOT NULL,
ORDER_CODE VARCHAR2(50),
ORDER_STATUS VARCHAR2(20),
ORDER_USER_ID NUMBER,
ORDER_DATE TIMESTAMP(6)
INSERT_AT TIMESTAMP(6),
UPDATED_AT TIMESTAMP(6),
PRIMARY KEY (ORDER_ID)
);
I have no idea how to do this and what is the best way (with a trigger, procedure, using merge, etc.)
Can someone give me a direction, please?
Here is some pseudo-code to show you a potential trigger based solution that does not fall back into slow row-by-row processing.
create or replace trigger mytrg
for insert or update delete on ordera
compound trigger
pklist sys.odcinumberlist;
before statement is
begin
pklist := sys.odcinumberlist();
end before statement ;
after each row is
begin
pklist.extend;
pklist(pklist.count) := :new.order_id;
end before each row;
after statement is
begin
merge into orderb b
using (
select a.*
from ordera a,
table(pklist) t
where a.order_id = t.column_value
) m
when matched then
update
set b.order_code = m.order_code,
b.order_status = m.order_status,
...
where decode(b.order_code,m.order_code,0,1)=1
or decode(b.order_status,m.order_status,0,1)=1
....
when not matched then
insert (b.order_id,b.order_code,....)
values (m.order_id,m.order_code,....);
end after statement ;
end;
We hold the impacted primary keys, and then build a single merge later, with an WHERE embed to minimise update activities.
If your application allows the update of primary keys, you'd need some additions, but this should get you started
I'm trying to validate the columns in the table ProjectDetails.TimeCards
create table ProjectDetails.TimeCards(
Time_Card_ID int identity (55,15),
Employee_ID int foreign key references HumanResources.Employees(Employee_ID),
Date_Issued date, --DateIssued should be greater than the current date and the project start date (Project start date is from another table).
Days_Worked int constraint chk_Days_Worked check(Days_Worked > '0'),
Project_ID int foreign key references ProjectDetails.Projects(Project_ID),
Billable_hours int constraint chk_Billable_Hours check (Billable_Hours > '0'),
Total_Cost money, -- should be automatically calculated by using the following formula: TotalCost=Billable Hours * BillingRate (billing rate is from another table)
Work_Code_ID int foreign key references ProjectDetails.WorkCodes(Work_Code_ID)
);
I tried building a trigger, but was only able to get the trigger to fire if the Date_Issued was less than the current date
CREATE TRIGGER dateissued
ON ProjectDetails.TimeCards
FOR INSERT
AS
DECLARE #ModifiedDate date
SELECT #ModifiedDate = Date_Issued FROM Inserted
IF (#ModifiedDate < getdate())
BEGIN
PRINT 'The modified date should be the current date. Hence, cannot insert.'
ROLLBACK TRANSACTION -- transaction is to be rolled back
END
i need the trigger to fire if the Date issued is less than the current date and also if date issued is less than the start_date. As for the billing rate calculation i'm lost there.
This is the other table
create table ProjectDetails.Projects(
Project_ID int identity (0100, 01) primary key, -- Primary key
Project_Name char (50) not null,
Start_Date date not null, -- the start date i'm referring to
End_Date date not null,
constraint CheckEndLaterThanStart check (End_Date > Start_Date),
Billing_Estimate money constraint chk_Billing_Estimate check (Billing_Estimate > '1000'),
Client_ID int Foreign Key references CustomerDetails.Clients(Client_ID)
);
I believe this provides the logic you are after. There are a couple of comments in the code for you:
CREATE TRIGGER trg_chk_Date_Issued ON ProjectDetails.TimeCards
FOR INSERT, UPDATE --I assume on need on UPDATE as well, as otherwise this won't validate
AS BEGIN
IF EXISTS(SELECT 1
FROM inserted i
JOIN ProjectDetails.Projects P ON i.Project_ID = P.Project_ID
WHERE i.Date_Issued < CONVERT(date,GETDATE())
OR i.Date_Issued < P.Start_Date) BEGIN
RAISERROR(N'Date Issued cannot be less than the current date or the Project Start Date.', 10,1); --Raised an error, rather than using PRINT
ROLLBACK;
END
END
Note that you may want a different trigger for UPDATE, as if you are updating the row, and Date_Issued has a value lower than the date of the UPDATE, the statement will fail.
So I have a column on my PAYMENT table that is called Status.. It has a foreign key of another table called reservation with Reservation_ID. The Reservation Table also has a status column and it will only get updated when there is a value in the status column of payment table. So If my status field in payment table has the value "Confirmed", the value for that particular Reservation_ID is supposed to turn to 1.. Otherwise 22. This is how I made the trigger:
CREATE OR REPLACE TRIGGER stats BEFORE INSERT OR DELETE OR UPDATE ON PAYMENT FOR EACH ROW
DECLARE
V_STATUS VARCHAR2(20);
BEGIN
SELECT Status INTO V_STATUS FROM PAYMENT INNER JOIN RESERVATION ON PAYMENT.Reservation_ID=RESERVATION.Reservation_ID WHERE PAYMENT.Reservation_ID=:NEW.Reservation_ID;
IF INSERTING AND V_STATUS='CONFIRMED' THEN
UPDATE RESERVATION SET status=1 WHERE Reservation_ID=:new.Reservation_ID;
ELSIF UPDATING AND V_STATUS='CONFIRMED' THEN
UPDATE RESERVATION SET status=1 WHERE Reservation_ID=:new.Reservation_ID;
ELSE
UPDATE RESERVATION SET status=22 WHERE Reservation_ID=:new.Reservation_ID;
END IF;
END;
So the trigger basically gets compiled but when I try inserting values inside Payment Table, I get the following error:
Error report -
ORA-01403: no data found
ORA-06512: at "ME.STATS", line 4
ORA-04088: error during execution of trigger 'ME.STATS'
create statments for both tables:
CREATE TABLE RESERVATION(RESERVATION_id NUMBER(10) NOT NULL, MEMBER_ID NUMBER(10) CONSTRAINT RE_MEM_fk REFERENCES MEMBER(MEMBER_ID) ON DELETE SET NULL,status NUMBER(10) CONSTRAINT RES_status_fk REFERENCES STATUS(RESERVATION_status_id) ON DELETE SET NULL, CONSTRAINT PK_BOOK PRIMARY KEY(RESERVATION_id));
CREATE TABLE PAYMENT(Payment_ID NUMBER(10) NOT NULL ,RESERVATION_id NUMBER(10) CONSTRAINT Pay_RES_fk REFERENCES RESERVATION(RESERVATION_id) ON DELETE SET NULL, TicketPrice NUMBER(10), ExtraFaciliFees Number(10),TOTAL_AMOUNT Number(10), PromotionalCode VARCHAR2(10), CONSTRAINT PK_PAY PRIMARY KEY(Payment_ID));
First :
CREATE TABLE RESERVATION(
Status NUMBER(10));
SELECT Status INTO V_STATUS
IF INSERTING AND V_STATUS='CONFIRMED'
Could you explain me how you expect a NUMBER to match a string ?
Next (from http://www.dba-oracle.com/sf_ora_01403_no_data_found.htm )
SELECT INTO clauses are standard SQL queries which pull a row or set
of columns from a database, and put the retrieved data into variables
which have been predefined.
If the SELECT INTO statement doesn't return at least on e row,
ORA-01403 is thrown.
So this :
SELECT
Status INTO V_STATUS
FROM PAYMENT p
INNER JOIN RESERVATION r
ON p.Reservation_ID = r.Reservation_ID
WHERE p.Reservation_ID = :NEW.Reservation_ID;
Is likely to output no row at all...
Agree with #Blag, below statement is giving the no data found exception.
In general if you want to know the exact line number the error is pointing to you can refer to the object via DBA_SOURCE or ALL_SOURCES.
SELECT
Status INTO V_STATUS
FROM PAYMENT p
INNER JOIN RESERVATION r
ON p.Reservation_ID = r.Reservation_ID
WHERE p.Reservation_ID = :NEW.Reservation_ID;
I am trying to update columns in my child table service after delete on parent table cars using function choose_ideal_car which uses some selects over cars and service tables.
Here is part of my sql script:
CREATE TABLE cars(car_id INT CONSTRAINT pk_id_cars);
CREATE TABLE service(
service_id INT CONSTRAINT pk_id_service PRIMARY KEY,
car_id INT CONSTRAINT fk_id_car REFERENCES cars(car_id) ON DELETE SET NULL,
period VARCHAR2(5) CONSTRAINT check_period CHECK period IN ('even','odd','every'),
period VARCHAR2(3) CONSTRAINT check_day CHECK day IN ('mon','tue','wed','thu','fri')
);
CREATE OR REPLACE TRIGGER service_set_car_id AFTER DELETE ON cars
DECLARE
CURSOR touched_rows is select * from service where car_id = null;
touched_row service%ROWTYPE;
BEGIN
OPEN touched_rows;
LOOP
FETCH touched_rows INTO touched_row;
EXIT WHEN touched_rows%NOTFOUND;
UPDATE service SET car_id = choose_ideal_car(touched_row.period,touched_row.day) WHERE service_id = touched_row.service_id;
END LOOP;
CLOSE touched_rows;
end;
/
For some reason my trigger is never fired.
I also tried creating triggers like this:
CREATE OR REPLACE TRIGGER service_set_car_id AFTER DELETE FROM cars FOR EACH ROW
CURSOR touched_rows is select * from service where car_id = :old.car_id;
...
Which is fired but throws 'mutating error' because function choose_ideal_car uses selects from both tables. Maybe the solution of this is to create duplicate of my cars table and select from it in my choose_ideal_car function instead of selecting from the cars table on which is my trigger defined, but that does not sounds good to me.
While I am writing this post I realized that even if my first trigger is fired it would not work correctly and throw the same 'mutating error'.
So in the end I have two questions:
1) Why is the first trigger never fired?
2) How to fix this mutating error and get all working correctly?
where car_id = null returns no rows, use where car_id is null instead