>"Pavel Stehule" <pavel.stehule@hotmail.com> writes:
> > root=# create table products(
> > barcode char(13) NOT NULL
> > check (barcode NOT similar to '%[^0-9]%')
> > );
>
> > root=# insert into products values('22');
> > ERROR: new row for relation "products" violates check constraint
> > "products_barcode_check"
>
> > root=# select '22' NOT similar to '%[^0-9]%';
> > ?column?
> > ----------
> > t
>
>That isn't a counterexample, because you forgot about the trailing
>spaces, which can match [^0-9].
>
>regression=# select '22' NOT similar to '%[^0-9]%';
> ?column?
>----------
> t
>(1 row)
>
>regression=# select '22'::char(13) NOT similar to '%[^0-9]%';
> ?column?
>----------
> f
>(1 row)
>
>
I see it now. Thank You. It's one trick from Joe Celko and I too late
understand it.
Nice day
Pavel Stehule
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