A sequence is used to generate id for a customer table and then using trigger to populate the id column as a varchar value.
The trigger is
CREATE OR REPLACE TRIGGER USER_ID_TRIGGER
before insert on CUSTOMER
REFERENCING NEW AS New OLD AS Old
for each row
begin
-- :new.user_id := 'CUST' || :new.user_id ;
select 'CUST' || SEQ_CUSTOMER_ID.nextval into :new.user_id from dual;
end USER_ID_TRIGGER;
So, each insert in the column is like 'CUST1', 'CUST3', etc.
The trigger can't be changed.
I am using hibernate save(customer) method to save customer objects in the db. Problem is the return id value I am getting is (as expected) different from the one that is ultimately saved in the table.
For example, if the id populated in the column is 'CUST19', the hibernate code returns 18.
My question is, if the code returns a value of 210, will it be safe for me to assume that the populated value is CUST211?
Related
Can anyone help me with this code below. There are 3 tables : Customer_A1, Reservation_A1 and Invoice_A1. I am writing a trigger that will execute every time a new reservation is made.
The trigger will pre-loaded the invoice table the information of invoice_id (inv_id), reservation_id (res_id), customer first name (cust_fname), customer last name (cust_lname) and reservation_start_date.
My code is below. There is no compilation errors when trigger is created. However when i insert a new row to Reservation table which makes the trigger execute, it inform me of that my trigger has an error of
ORA-01422: fetch returns more than requested number of rows.
CREATE OR REPLACE TRIGGER invoice_after_reservation_made
AFTER INSERT
ON RESERVATION_A1
FOR EACH ROW
DECLARE
inv_id INVOICE_A1.INV_ID%type;
res_id INVOICE_A1.res_id%type;
room_id INVOICE_A1.room_id%type;
cust_fname INVOICE_A1.cust_fname%type;
cust_lname INVOICE_A1.cust_lname%type;
reservation_start_date INVOICE_A1.reservation_start_date%type;
cust_id RESERVATION_A1.cust_id%type;
BEGIN
--read reservation_id
res_id:= :new.res_id;
--read room_id
room_id:= :new.room_id;
--read reservation_start_date
reservation_start_date:= :new.reservation_start_date;
--read customer_id
cust_id:= :new.cust_id;
--create new invoice_id
SELECT MAX(INVOICE_A1.inv_id)+1 INTO inv_id FROM INVOICE_A1;
-- import value from CUSTOMER_A1 table to variable cust_fname, cust_lname
Select CUSTOMER_A1.cust_fname,CUSTOMER_A1.cust_lname INTO
cust_fname,cust_lname
FROM CUSTOMER_A1
WHERE CUSTOMER_A1.cust_id=cust_id;
-- Insert record into invoice table
INSERT INTO INVOICE_A1
VALUES (inv_id,res_id,room_id,cust_fname,cust_lname,null,TO_DATE(TO_CHAR(reservation_start_date),'DD/MM/YYYY'),null);
END;
Note: I have looked up for solution on internet however no cigar though. People said the problem mostly come from Select statements that return more than one row. However my Select query in the code above return only one row. I also check the table's data, No entity and referential integrity are violated in 3 tables Customer_A1, Reservation_A1 and Invoice_A1. I even copy a code to a separate test procedure to print out all variables after reading inputs. The test procedure work well. I surrender now. Please help me with this problem. I am new . Thanks
The problem is in the statement
Select CUSTOMER_A1.cust_fname,CUSTOMER_A1.cust_lname INTO
cust_fname,cust_lname
FROM CUSTOMER_A1
WHERE CUSTOMER_A1.cust_id=cust_id;
You probably meant this to mean "Find data from CUSTOMER_A1 where CUSTOMER_A1.cust_id = the value of the variable 'cust_id'". Unfortunately, that's not how it's interpreted. The database is reading this as "Find data from CUSTOMER_A1 where CUSTOMER_A1.cust_id = CUSTOMER_A1.cust_id" - in other words, it's comparing the CUST_ID field of each row to itself, finding that they're equal (except in the case of NULL values), and returns data from that row.
A good rule to remember when writing PL/SQL is "Never give a variable the same name as a column you'll be manipulating". With this in mind, you might consider rewriting your trigger as:
CREATE OR REPLACE TRIGGER invoice_after_reservation_made
AFTER INSERT
ON RESERVATION_A1
FOR EACH ROW
DECLARE
vInv_id INVOICE_A1.INV_ID%type;
vRes_id INVOICE_A1.res_id%type;
vRoom_id INVOICE_A1.room_id%type;
vCust_fname INVOICE_A1.cust_fname%type;
vCust_lname INVOICE_A1.cust_lname%type;
vReservation_start_date INVOICE_A1.reservation_start_date%type;
vCust_id RESERVATION_A1.cust_id%type;
BEGIN
--read reservation_id
vRes_id:= :new.res_id;
--read room_id
vRoom_id:= :new.room_id;
--read reservation_start_date
vReservation_start_date:= :new.reservation_start_date;
--read customer_id
vCust_id:= :new.cust_id;
--create new invoice_id
SELECT MAX(INVOICE_A1.inv_id)+1 INTO vInv_id FROM INVOICE_A1;
-- import value from CUSTOMER_A1 table to variable cust_fname, cust_lname
Select CUSTOMER_A1.cust_fname,CUSTOMER_A1.cust_lname
INTO vCust_fname, vCust_lname
FROM CUSTOMER_A1
WHERE CUSTOMER_A1.cust_id=cust_id;
-- Insert record into invoice table
INSERT INTO INVOICE_A1
VALUES (vInv_id, vRes_id, vRoom_id, vCust_fname, vCust_lname, null,
TO_DATE(TO_CHAR(reservation_start_date),'DD/MM/YYYY'), null);
END invoice_after_reservation_made;
/* Formatted on 24/09/2015 09:36:39 (QP5 v5.215.12089.38647) */
CREATE OR REPLACE TRIGGER TR_student_PREF_sub_UPDATE
AFTER INSERT OR UPDATE
ON student
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
DECLARE
v_preferred_sub_value NUMBER (1);
no_project_record EXCEPTION;
BEGIN
IF UPDATING OR INSERTING
THEN
IF (:NEW.is_sub = 0 AND :NEW.standard_id IS NOT NULL)
THEN
SELECT preferred_sub
INTO v_preferred_sub_value
FROM STANDARD
WHERE standard_id = :NEW.standard_id;
ELSIF (:NEW.is_sub = 1 AND :NEW.subject_id IS NOT NULL)
THEN
SELECT preferred_sub
INTO v_preferred_sub_value
FROM admin_subject.source
WHERE source_id = :NEW.subject_id;
END IF; /* v_preferred_sub_value IS NOT NULL THEN UPDATE preferred_sub VALUE IN student TABLE */
IF (v_preferred_sub_value IS NOT NULL)
THEN
UPDATE student
SET preferred_sub = v_preferred_sub_value
WHERE student_id = :NEW.student_id;
COMMIT;
END IF;
END IF;
EXCEPTION
WHEN NO_PROJECT_RECORD
THEN
NULL;
END TR_student_PREF_sub_UPDATE;
Process : When the user click save action from UI, this invoke insert method in java code. While inserting values into subject table, trigger called and checking is_sub value if 0 then fetching preferred_sub value from standard table. If the is_sub = 1 then fetching preferred_sub from admin_subject.source schema table.
Based on v_preferred_sub_value it is trying to update subject table which was newly inserted row.
I ran the insert action from UI, after the trigger called, i checked the subject table with preferred_sub column it shows null value.
Please help me, what i made the mistake over there.
student table have student_id, subject_id, standard_id and is_sub values and more.
standard table & student table are in same schema.
source is different schema which has grant all privileged.
Change your trigger to a before trigger and assign the determined values to the appriopriate :new pseudo column. The database will take care of the rest.
IF (v_preferred_sub_value IS NOT NULL)
THEN
:NEW.preferred_sub = v_preferred_sub_value;
END IF;
The value of :NEW.preferred_sub will now be placed in the table record.
This is so simple it has probably already been asked, but I couldn't find it (if that's the case I'm sorry for asking).
I would like to insert an empty row on a table so I can pick up its ID (primary key, generated by an insert trigger) through an ExecuteScalar. Data is added to it at a later time in my code.
My question is this: is there a specific insert syntax to create an empty record? or must I go with the regular insert syntax such as "INSERT INTO table (list all the columns) values (null for every column)"?
Thanks for the answer.
UPDATE: In Oracle, ExecuteScalar on INSERT only returns 0. The final answer is a combination of what was posted below. First you need to declare a parameter, and pick up it up with RETURNING.
INSERT INTO TABLENAME (ID) VALUES (DEFAULT) RETURNING ID INTO :parameterName
Check this out link for more info.
You would not have to specify every single column, but you may not be able to create an "empty" record. Check for NOT NULL constraints on the table. If none (not including the Primary Key constraint), then you would only need to supply one column. Like this:
insert into my_table ( some_column )
values ( null );
Do you know about the RETURNING clause? You can return that PK back to your calling application when you do the INSERT.
insert into my_table ( some_column )
values ( 'blah' )
returning my_table_id into <your_variable>;
I would question the approach though. Why create an empty row? That would/could mean there are no constraints on that table, a bad thing if you want good, clean, data.
Basically, in order to insert a row where values for all columns are NULL except primary
key column's value you could execute a simple insert statement:
insert into your_table(PK_col_name)
values(1); -- 1 for instance or null
The before insert trigger, which is responsible for populating primary key column will
override the value in the values clause of the insert statement leaving you with an
empty record except PK value.
I am having problems with this code below, which is a trigger used in Oracle SQL:
CREATE OR REPLACE TRIGGER TRG_TUTOR_BLOCK
BEFORE INSERT OR UPDATE ON tutors
FOR EACH ROW
DECLARE
BEGIN
IF :new.tutorName = :old.tutorName
THEN
RAISE_APPLICATION_ERROR(-20101, 'A tutor with the same name currently exists.');
ROLLBACK;
END IF;
END;
/
This trigger is used to prevent users from entering the same tutor name at different records.
After I insert two records with the same tutorname, the trigger does not block me from inserting it. Is there anyone can tell me what are the problems with this coding? Here are the sample format and insert values:
INSERT INTO tutors VALUES (tutorID, tutorName tutorPhone, tutorAddress, tutorRoom, loginID);
INSERT INTO tutors VALUES ('13SAS01273', 'Tian Wei Hao', '019-8611123','No91, Jalan Wangsa Mega 2, 53100 KL', 'A302', 'TianWH');
Trigger in Kamil's example will throw ORA-04091, you can see this with your own eyes here. ROLLBACK in a trigger is unnecessary, it runs implicitly when a trigger makes a statement to fail.
You can prohibit any DML on table by altering it with read only clause:
alter table tutors read only;
At last, integrity should be declarated with integrity constraints and not with triggers.
Good luck!
You don't need a trigger for this in Oracle.
You can do it with an "unique index" on the tutorName column (see http://docs.oracle.com/cd/B28359_01/server.111/b28310/indexes003.htm#i1106547).
Note: about your trigger, it fails on checking for another record with the same tutorName because it's not scanning the tutors table for another record with the same tutorName, it's just comparing the tutorName values of the row you are creating (in this case, old.tutorName is just NULL, because the row doesn't exist yet).
Check the case in yours trigger body
IF :new.tutorName = :old.tutorName
It returns true only if 'tutorName' value is the same in new and old record. When you'll trying to updat some value you'll get
IF 'someTutorName' = 'someTutorName'
which will return TRUE.
Inserting row cannot fire this rule because you're trying to compare something like that:
'someTutorName' = NULL
This case always returns FALSE.
Try to use something like that
CREATE OR REPLACE TRIGGER TRG_TUTOR_BLOCK
BEFORE INSERT OR UPDATE ON tutors
FOR EACH ROW
DECLARE
rowsCount INTEGER;
BEGIN
SELECT COUNT(*) FROM tutors WHERE tutorName is :new.tutorName INTO rowsCount;
IF rowsCount > 0
THEN
RAISE_APPLICATION_ERROR(-20101, 'A tutor with the same name currently exists.');
ROLLBACK;
END IF;
END;
/
But the best solution is the one mentioned by friol - use unique index by executing SQL like this
ALTER TABLE tutors
ADD CONSTRAINT UNIQUE_TUTOR_NAME UNIQUE (tutorName);
If you wanna completely ignore recording a row to a table you can follow these steps
rename table to something else and create a view with the same name and create an instead of trigger.
create table usermessages (id number(10) not null)
GO
alter table usermessages rename to xusermessages
GO
create or replace view usermessages as (select * from xusermessages)
GO
create or replace trigger usermessages_instead_of_trg
instead of insert or update on usermessages
for each row
begin
Null ;
end ;
GO
insert into usermessages(123)
Live test available here below
http://sqlfiddle.com/#!4/ad6bc/2
When writing a row-level trigger in Oracle, I know that you can use the OLD and NEW pseudo-records to reference the old and new state of the row that fired the trigger. I know that in an INSERT trigger OLD doesn't contain any data, but I'm not sure how this affects the evaluation of a WHEN clause for that trigger. For example, if I have the following trigger:
CREATE OR REPLACE TRIGGER mung_row
BEFORE INSERT OR UPDATE ON some_table
FOR EACH ROW
BEGIN
:NEW.foo = 'some val';
END;
and I want to modify this trigger to only run on an update when foo was previously null, but always run on an insert, I could satisfy the update part of the change by adding a WHERE clause:
CREATE OR REPLACE TRIGGER mung_row
BEFORE INSERT OR UPDATE ON some_table
FOR EACH ROW
WHEN (OLD.foo IS NULL)
BEGIN
:NEW.foo = 'some val';
END;
Will this cause problems in the insert case? What will OLD.foo evaluate to in the INSERT?
I'm aware that I could split the INSERT and UPDATE triggers or use INSERTING/UPDATING/DELETING in the trigger body, but I'd rather not in the case that inspired this question.
When a record is being inserted, every field of OLD will be NULL, including the fields marked as NOT NULL in the table's definition.
For example, suppose your table has a non-nullable column named id:
CREATE TABLE some_table (
id NUMBER NOT NULL,
foo VARCHAR2(100)
)
When a record is inserted into this table, OLD.id will be NULL. However, when a record is updated in this table, OLD.id will not be NULL. Because you only want to change :NEW.foo if a record is being updated, you just have to check to see if OLD.id has a non-null value.
CREATE OR REPLACE TRIGGER mung_row
BEFORE INSERT OR UPDATE ON some_table
FOR EACH ROW
WHEN (OLD.id IS NOT NULL AND OLD.foo IS NULL)
BEGIN
:NEW.foo = 'some val';
END;