Re: UTF8 encoding and non-text data types - Mailing list pgsql-sql

On Jan 13, 2008 8:51 PM, Steve Midgley <public@misuse.org> wrote:

At 02:22 PM 1/13/2008, pgsql-sql-owner@postgresql.org wrote:

>Date: Sat, 12 Jan 2008 14:21:00 -0800

>From: "Medi Montaseri" < montaseri@gmail.com>

>To: pgsql-sql@postgresql.org

>Subject: UTF8 encoding and non-text data types

>Message-ID:

>< 8078a1730801121421l1c9b90c1lc65d36cf6e752a6f@mail.gmail.com>

>

>I understand PG supports UTF-8 encoding and I have sucessfully

>inserted

>Unicode text into columns. I was wondering about other data types such

>as

>numbers, decimal, dates

>

>That is, say I have a table t1 with

>create table t1 { name text, cost decimal }

>I can insert UTF8 text datatype into this table with no problem

>But if my application attempts to insert numbers encloded in UTF8,

>then I

>get wrong datatype error

>

>Is the solution for the application layer (not database) to convert

>the

>non-text UTF8 numbers to ASCII and then insert it into database ?

>

>Thanks

>Medi

Hi Medi,

I have only limited experience in this area, but it sounds like you

sending your numbers as strings? In your example:

>create table t1 { name text, cost decimal };

insert into t1 (name, cost) values ('name1', '1');

I can't think of how else you're sending numeric values as UTF8? I know

that Pg will accept numbers as strings and convert internally (that has

worked for me in some object relational environments where I don't

choose to cope with data types), but I think it would be better if you

simply didn't send your numeric data in quotations, whether as UTF8 or

ASCII. If you don't have control over this layer (that quotes your

values), then I'd say converting to ASCII would solve the problem. But

better to convert to numeric and not ship quoted strings at all.

I may be totally off-base and missing something fundamental and I'm

very open to correction (by anyone), but that's what I can see here.

Best regards,

Steve

At 11:01 AM 1/14/2008, Medi Montaseri wrote:

Thanks Steve,

Actually I do not insert text data into my numeric field.
As I mentioned given
create table t1 { name text, cost decimal }
then I would like to insert numeric data into column "cost" because then I can later benefit from numerical operators like SUM, AVG, etc

More specifically, I am using HTML, Perl and PG. So from the HTML point of view a textfield is just some strings. So my user would enter 12345 but expressed in UTF8. Perl would get this and use DBI to insert it into PG

What I am experiencing now is that DB errors that I am trying to insert an incorrect data into column "cost" which is numeric and the data is coming in from HTML in UTF8

Mybe I have to convert it to ASCII numbers in Perl before inserting  them into PG

Thanks
Medi

Hi Medi,

I agree that you should convert your values in Perl before handing to DBI. I'm not familiar with DBI but presumably if you're sending it UTF8 values it's attempting to quote them or do something with them, that a numeric field in Pg can't handle. Can you trap/monitor the exact sql statement that is generated by DBI and sent to Pg? That would help a lot in knowing what it is doing, but I suspect if you just convert your numbers from the HTML/UTF8 source values into actual Perl numeric values and then ship to DBI you'll be better off. And you'll get some input validation for free.

I hope this helps,

Steve