Selecting large sequence value into global variable not working in PL/SQL code - sql

Question

I have a script where I would like to have a global variable to store a transaction number for later use. The code is working fine on one schema where the sequence value that I'm fetching is relatively low. It is not working on another schema with a higher sequence value where I get a "Numeric Overflow". If I change that sequence value to a lower number it is working as well but that is not an option.
VAR TRANSACTIONNR NUMBER;
BEGIN
--Works with NEXTVAL being around 946713241
--Doesn't work with NEXTVAL being around 2961725541
SELECT MY_SEQUENCE.NEXTVAL INTO :TRANSACTIONNR FROM DUAL;
MY_PACKAGE.STARTTRANSACTION(:TRANSACTIONNR);
END;
/
-- SQL Statements
BEGIN
MY_PACKAGE.ENDTRANSACTION;
MY_PACKAGE.DO_SOMETHING(:TRANSACTIONNR);
END;
/
What is also working is selecting the sequence into a variable declared in the DECLARE block:
DECLARE
TRANSACTIONNR NUMBER;
BEGIN
SELECT MY_SEQUENCE.NEXTVAL INTO TRANSACTIONNR FROM DUAL;
MY_PACKAGE.STARTTRANSACTION(TRANSACTIONNR);
END;
/
But that means I won't be able to reuse it in the block at the end. Setting the size of the number is not possible.
VAR TRANSACTIONNR NUMBER(15)
is not valid.
Any ideas what I could try or other ways to store global state?

Answer 1

On further investigation this looks like it might be a SQL Developer bug (making assumptions about what you're doing again, of course...). I can get the same error with:
VAR TRANSACTIONNR NUMBER;
BEGIN
SELECT 2961725541 INTO :TRANSACTIONNR FROM DUAL;
END;
/
It appears that SQL Developer's NUMBER is limited to 2^31, which isn't the case normally for Oracle.
A possibly workaround is to use BINARY_FLOAT to store the value, but you'll run into precision problems eventually (not sure where, but looks OK up to 2^53-ish), and you'll need to cast() it back to NUMBER when using it.
VAR TRANSACTIONNR BINARY_DOUBLE;
BEGIN
SELECT 2961725541 INTO :TRANSACTIONNR FROM DUAL;
-- dbms_output.put_line(cast(:TRANSACTIONNR as NUMBER)); -- null for some reason
END;
/
...
BEGIN
dbms_output.put_line(cast(:TRANSACTIONNR as NUMBER));
END;
/
For some reason I don't seem to be able to refer to the bind variable again in the anonymous block I set it in - it's null in the commented-out code - which seems to be another SQL Developer quirk, regardless of the var type; but as you were doing so in your code, I may again have assumed too much...
Original answer for posterity, as it may still be relevant in other circumstances...
Presumably you're doing something to end the current transaction, e.g. a commit in endtransaction; otherwise you could just refer to my_sequence.currval in the do_something call. A number variable is fine for this size of number though, it won't have a problem with a sequence that size, and it won't make any difference that it is from a sequence rather than manually assigned. I don't think the problem is with the storage or the sequence.
It seems rather more likely that the error is coming from one of the package procedures you're calling, though I can't quite imagine what you might be doing with it; something like this will cause the same error though:
create sequence my_sequence start with 2961725541;
create package my_package as
procedure starttransaction(v_num number);
procedure endtransaction;
procedure do_something(v_num number);
end my_package;
/
create package body my_package as
procedure starttransaction(v_num number) is
begin
dbms_output.put_line('starttransaction(): ' || v_num);
for i in 1..v_num loop
null;
end loop;
end starttransaction;
procedure endtransaction is
begin
dbms_output.put_line('endtransaction()');
end endtransaction;
procedure do_something(v_num number) is
begin
dbms_output.put_line('do_something(): ' || v_num);
end do_something;
end my_package;
/
When your code is run against that it throws your error:
BEGIN
*
ERROR at line 1:
ORA-01426: numeric overflow
ORA-06512: at "STACKOVERFLOW.MY_PACKAGE", line 6
ORA-06512: at line 5
endtransaction()
do_something():
Note the error is reported against line 6 in the package, which is the for ... loop line, not from the assignment in your anonymous block.
Looping like that would be an odd thing to do of course, but there are probably other ways to generate that error. The breakpoint for it working is if the nextval is above 2^31. If I start the sequence with 2147483647 it works, with 2147483648 it errors.
I'm assuming you are actually getting an ORA-01426 from the original question; if it's actually a ORA-1438 or ORA-06502 then it's easier to reproduce, by trying to assign the value to a number(9) column or variable. 'Numeric overflow' is pretty specific though.