I am brand new to SQL, and I am learning on an SQLite editor. So I create a couple of very simple tables. This code is straight from Linkedin learning "SQL essential training", and I am using the recommended SQLite editor.
CREATE TABLE widgetInventory(
id INTEGER PRIMARY KEY,
description TEXT,
onhand INTEGER NOT NULL);
CREATE TABLE widgetSales(
id INTEGER PRIMARY KEY,
inv_id INTEGER,
quan INTEGER,
price INTEGER);
Then I update widgetInventory with some data:
INSERT INTO widgetInventory (description, onhand) VALUES ('rock', 25);
INSERT INTO widgetInventory (description, onhand) VALUES ('paper', 25);
INSERT INTO widgetInventory (description, onhand) VALUES ('scissors', 25);
Next, I want to update the widgetSales table with a sale, and update the widgetInventory table to record the reduction of onhand.
BEGIN TRANSACTION;
INSERT INTO widgetSales (inv_id, quan, price) VALUES (1,5,500);
UPDATE widgetInventory SET onhand = (onhand-5) WHERE id = 1;
END TRANSACTION;
I am not understanding why this gives me an error when I run it, as it is exactly as it is in the lesson.
[06:18:04] Error while executing SQL query on database 'test': cannot start a transaction within a transaction
But, I can run the INSERT and UPDATE lines separately, and they do what I want them to do.
Apparently, running - END TRANSACTION; - before running the entire transaction appears to work.
I think that somehow, SQL thinks that a transaction is already occurring. Though, I'm not sure where exactly. So to stop it, you have to end the transaction first before proceeding with the course.
In the SQLite Editor, you may have to delete or comment out all of the code before and after these two transactions.
BEGIN TRANSACTION;
INSERT INTO widgetSales ( inv_id, quan, price ) VALUES ( 1, 5, 500 );
UPDATE widgetInventory SET onhand = ( onhand - 5 ) WHERE id = 1;
END TRANSACTION;
BEGIN TRANSACTION;
INSERT INTO widgetInventory ( description, onhand ) VALUES ( 'toy', 25 );
ROLLBACK;
Otherwise it won't execute the transaction.
Other than that, there is probably an error written in somewhere. Copying and pasting in the .txt file didn't give me that transaction error and could execute the transaction normally.
Just had this same error and my issue was I only highlighted the first line so SQLLite started the transaction but didn't run it fully. All I did was run end transaction, highlight the whole block of code and run that and it worked fine. Must be some syntax issue in Lite that doesn't run the full block itself.
while executing SQL query on database 'test': cannot start a
transaction within a transaction
means a transaction already exists. It may happen if someone forgets to select the END TRANSACTION; statement.
If you face this issue just select END TRANSACTION once and run. With this it will end the active transaction and then you can run any of the existing transaction.
For the particular case of following the Linkedin learning "SQL essential training" course, I have figured out to fix it by running (f9) the "BEGIN TRANSACTION", "...TRANSACTION CONTENTS..." and "END TRANSACTION" statements separately, not all the statements at the same time.
So,
First select the "BEGIN TRANSACTION;" and run it by pressing f9.
Then select the contents of the transactions (I think you can include also the "END TRANSACTION;" part) and run it.
Related
I am creating a book tracking database for myself that holds information about my books and allows me to keep track of who is borrowing them. I am trying to create a trigger on my Checkouts table that runs if a record is added or updated that will determine if a checkout data has been entered or if a checkin date has been entered and change the "available" field in my Books table to "Y" or "N".
I have created a trigger called "update_book_availablility" on my Checkouts table but I keep getting this error:
"PLS-00103: Encountered the symbol 'end-of-file' when expecting one of the following: ( begin case declare and exception exit for goto if loop mod null pragma raise return select update while with <<continue close current delete fetch lock insert open rollback savepoint set sql execute commit forall merge standard pipe purge json_object
Errors: check compiler log"
Here is my trigger code:
CREATE OR REPLACE NONEDITIONABLE TRIGGER "UPDATE_BOOK_AVAILABILITY"
AFTER INSERT OR UPDATE OF ISBN, PersonID, checkout_date, checkin_date
ON Checkouts
FOR EACH ROW
BEGIN
IF :NEW.checkout_date = NULL
THEN
UPDATE Book
SET available = 'N'
WHERE ISBN IN (SELECT :NEW.ISBN FROM Checkouts);
END IF;
END;
Here is an image of my ERD:
ERD
I have been looking into and double checking my trigger syntax, If condition syntax, subquery syntax, and googling this error but have found nothing that has helped. I am new to PL/SQL and would appreciate any help in understanding what I have done wrong or missed.
PLS-00103: Encountered the symbol end-of-file error is SYNTAX ERROR
Copied your trigger and adjusted it to one of my test tables - it works. I removed NONEDITIONABLE and changed trigger table name as well as column names and table/column beeing updated by trigger.
To Do:
Check your syntax again or write the trigger from scratch once more
"...WHERE ISBN IN (SELECT :NEW.ISBN FROM Checkouts)..." selects one fixed value (FOR EACH ROW) :NEW.ISBN of triggering table, better ->> "... WHERE ISBN = :NEW.ISBN ..."
Prety sure that you don't need NONEDITIONABLE trigger for your books tracking app...
Regards...
Is it possible to have insert statement outside of the scope of a transaction in a Stored Proc?
So there is a stored proc that writes some inserts, as part of a transaction
The reason for this is to write to Audit table and keep the audit records even if the stored proc fails or gets an exception
clarification, sorry if it was not clear, I am writing multiple audits for each action of the procedure so I can keep track what it did and what failed. not just a single Audit when there is an exception...
CREATE OR REPLACE PROCEDURE sampleProc
IS
BEGIN
start a transaction
INSERT to table 1
write to audit table about insert 1
INSERT to table 2
write to audit table about insert 2
INSERT to table 3
write to audit table about insert 3
INSERT to table 4
write to audit table about insert 4
if there is an exception - rollback except audit
all ok? commit.
END;
/
Yes, there is an option to perform actions in a separate transaction running simulteneously with your main one. See detail here
Example:
create table logs(creation_date date default sysdate, msg varchar2(4000));
create or replace procedure log_proc(sMessage varchar2)
is
pragma autonomous_transaction;
begin
insert into logs(msg)
values(sMessage);
commit; -- don't forget to commit in this separate transaction
end;
/
begin
log_proc('some message');
rollback;
end;
/
select * from logs
What you're after is PRAGMA AUTONOMOUS_TRANSACTION, which kicks off the module using it in a separate session.
Your code would be something like:
CREATE OR REPLACE PROCEDURE sample_proc
AS
procedure audit_insert (<params>)
is
pragma autonomous_transaction;
begin
<log details>
commit;
end audit_insert;
BEGIN
<INSERT to table 1>;
audit_insert(...);
<INSERT to table 2>;
audit_insert(...);
...
EXCEPTION
when others then
rollback;
raise;
END sample_proc;
/
Doing it like this would mean your audit details would be saved regardless of whether the calling code succeeds or fails.
N.B. I've created the audit_insert as a sub procedure of sample_proc. You would do better to have the code as individual procedures inside a package, rather than as one or more procedures.
I have searched extensively on this and I have found a lot of people asking the question but no answers that included code examples to help me understand.
I'd like to write a transaction (in sql using the command line sqlite3 interface) that performs several update statements, and if any of them fail for any reason, rolls back the transaction. The default behaviour appears to be to roll-back the statement that failed but commit the others.
This tutorial appears to advise that it's sufficient to add begin; and rollback; before and after the statements, but that's not true because I've tried it with deliberate errors and the non-error statements were definitely committed (which I don't want).
This example really confuses me because the two interlocutors seem to give conflicting advice at the end - one says that you need to write error handling (without giving any examples) whereas the other says that no error handling is needed.
My MWE is as follows:
create table if not exists accounts (
id integer primary key not null,
balance decimal not null default 0
);
insert into accounts (id, balance) values (1,200),(2,300);
begin transaction;
update accounts set balance = field1 - 100 where id = 1;
update accounts set balance = field1 + 100 where id = 2;
update accounts set foo = 23; //Deliberate error
commit;
The idea is that none of these changes should be committed.
The sqlite3 command-line shell is intended to be used interactively, so it allows you to continue after an error.
To abort on the first error instead, use the -bail option:
sqlite3 -bail my.db < mwe.sql
If you are executing line by line, then the idea is that you first run these commands:
create table if not exists accounts (
id integer primary key not null,
balance decimal not null default 0
);
insert into accounts (id, balance) values (1,200),(2,300);
begin transaction;
update accounts set balance = field1 - 100 where id = 1;
update accounts set balance = field1 + 100 where id = 2;
update accounts set foo = 23; //Deliberate error
At this point, if you have no errors, you run the commit:
commit;
All the updates should be visible if you open a second connection and query the table.
On another hand if you got an error, instead of committing you rollback:
rollback;
All the updates should be rolled back;
If you are doing it programatically in java you would enclose the updates in a try - catch block, and commit at the end of the try, or rollback inside the catch.
Oracle 11g/XE
Toad 12.7.1.11
I have a newly-installed db. Connected as SYS, created a user called 'jasons' with password and granted DBA. Disconnected and reconnected as 'jasons'. Then ran the following script:
CREATE SEQUENCE people_seq
MINVALUE 0
MAXVALUE 10000
START WITH 0
INCREMENT BY 1
CACHE 20;
commit;
create table people (PID number(10), FirstName varchar(20), LastName varchar(20));
commit;
alter table people add (constraint people_pk primary key (PID));
commit;
CREATE OR REPLACE TRIGGER people_trig
BEFORE INSERT ON people
FOR EACH ROW
BEGIN
SELECT people_seq.NEXTVAL
INTO :new.pid
FROM dual;
END;
commit;
When I run the script, everything goes well until the CREATE TRIGGER section. It throws:
ORA-04089: cannot create triggers on objects owned by SYS
I just created that very table as jasons! Can somebody please tell me what's going on?
Duh...
When making a new connection in Toad there's a nice little dropdown box in the middle of the right-hand side that says "Connect As" with your choice of Normal, SYSDBA, and SYSOPER.
It defaults to SYSDBA -- but when you select 'Normal'... Well... The above script works just fine ;-)
I have started SQlite 2-days ago, and today i tried to learn Transactions in Sqlite3. But i am unable to even run the simplest ever transaction.
Begin;
Insert into newTable(Name,Age) values ("Adnan Ahamd KHan",24)
Insert into tbl2 (Name, FID) values ("Adnan",(Select MAx(ID) from newTable))
END Transaction;
Error Displayed is
cannot start a transaction within a transaction: Begin;
Here we go,
I found the answer to my Questio. Actually i am using DBBrowser for SQlite. And upto my knowledge, you have to commit every statement in DBBrowser for SQlite.
I First created Tables, established Relationship, and without committing them all, i then tried to start that Transaction, that's why it was saying
cannot start a transaction within a transaction: Begin;
What i did, first issued a single
commit
to commit the statements which created tables, and then started Transaction. And it worked fine.
Thanks
I looked into the code and found BEGIN TRANSACTION; starting line and Commit; ending line. I removed both (remove the first and last line which says BEGIN TRANSACTION and Commit/ END TRANSACTION) of them and it works now.
The following failed for me:
BEGIN TRANSACTION;
....
END TRANSACTION;
AND
BEGIN TRANSACTION;
....
Commit;