Re: Prevent characters not transposable to LATIN9

Le 1/07/2010 16:48, Sam Mason a écrit :
> On Tue, Jun 29, 2010 at 04:52:22PM +0200, Arnaud Lesauvage wrote:
>> We have a database in UTF8, from which we have to export text files in
>> LATIN9 encoding (or WIN1252, which is almostthe same I believe).
>>
>> Records are entered via MSAccess forms (on psqlodbc-linked tables).
>> The problem is that some of the characters input by the users have no
>> equivalent in LATIN9.
>>
>> How could I easily write a CONSTRAINT (or RULE) that would check that
>> everything entered in the fields have an equivalent in my specific
>> destination encoding ?
>
> How about using the built in character conversion routines. Something
> like:
>
> col = convert_from(convert_to(col, 'LATIN9'),'LATIN9')
>
> as the check constraint, or its inverse as the where clause for the
> erroneous rows?

What happens then for a character that does not have an equivalent in
LATIN9 ?
If an error is raised in the check constraint, does it look like a
normal check error ?