>Hello everybody,
>
>I need to split an input string and import some data in tables, like this
>(simplified) ‘123423453456’
>In this case, the value 1 is 1234, value 2 = 2345. With a while loop the
>values were inserted, if I get an error (value is not a integer), then I will
>delete all records with this import-id.
>
>Now, value 1 should be add to an total counter, f. e. old value = 10000, new =
>11234. If I get an error, I would like to return to the old value. Now I have
>the following idea,
>I create a new column named tmp_insert an enter the value to add. If all
>records were inserted without any errors, I can add the new value to the total
>one and reset the column
>to 0. Now my question, how handled firebird this with concurrency, if I call
>the stored procedure more than once a time. Will ervery step worked to the end
>before the new call runs?
>Can it be problematic? (column tmp_insert and add to the total value)
Having one record with a total value is almost the same as doing things serial
rather than parallel, so avoid this if concurrency is an issue.
Rather than changing the value from 10000 to 11234, insert a new record into
the summation table with the value 1234. And rather than subtracting upon
deletes, insert a new record with a negative value. To get the total value,
query sum(TotalCounter) rather than just TotalCounter.
Every once in a while (typically in a batch run during the night), do something
like (I've added a group field, often you want to store more than one value -
feel free to use a stored procedure rather than execute block).
EXECUTE BLOCK as
declare variable SomeGroup integer;
declare variable NewSum integer;
begin
for select MyGroup, sum(TotalCounter)
from MyTable
group by MyGroup
into :SomeGroup, :NewSum do
begin
delete from MyTable
where MyGroup = :SomeGroup;
insert into MyTable(MyGroup, TotalCounter)
values(:SomeGroup, :NewSum);
end
end
No need for any tmp_insert column.
HTH,
Set
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