On 12/19/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Oliver Jowett <oliver@opencloud.com> writes:
> > Daniel Migowski wrote:
> >> I think a VARCHAR(50) and text are not interchangeable.
>
> > But a "varchar" (with no limit) and "text" *are* interchangeable, which
> > is why we identify text as VARCHAR
>
> But note that varchar-with-no-limit is itself a Postgres-ism: it's
> not allowed by the standard.
I was about to write the same thing. For educational value, this is
what a popular closed-source dbms will tell you:
SQL> create table a ( a varchar );
create table a ( a varchar )
*
ERROR at line 1:
xxx-00906: missing left parenthesis
SQL> create table a (a varchar(4001));
create table a (a varchar(4001))
*
ERROR at line 1:
xxx-00910: specified length too long for its datatype
SQL> create table a (a varchar(4000));
Table created.
That's right, textual data longer than 4000 characters needs to go
through the CLOB interface. And my license doesn't permit me to say
what that does to performance :)
So what Daniel is trying to say here is that Crystal Report probably
croaks on a column for the type is Types.VARCHAR but which does not
have a maximum length associated with it.
I think his patch is good.
jan