IDS Forum

Re: Informix 12 Unicode

Posted By: Fernando Nunes
Date: Tuesday, 21 October 2014, at 11:58 a.m.

In Response To: Re: Informix 12 Unicode (Fernando Nunes)

I feel I need to explain a bit better.
I agree the way we handle UTF-8 is not perfect. But It's not clear to me
what are the real requirements and complains...

1- SQL_LOGICAL_CHAR seems a bit useless... I'd prefer something at column
level

2- Even if we could specify the CHAR length, would that help? I find it a
bit weird how to handle that... would we "enlarge" the field automatically?
We use CHARs for a reason... the fact that they don't "expand" brings a lot
of advantages. And what would happen if the expansion would hit the maximum
size (VARCHAR 255)

3- Why would a developer need to know the CHAR specification? He should be
able to understand is a value fits or not... (more on this later)

4- I HATE the fact that we truncate data without errors... this can be
specially bad in UTF-8 databases or when we're storing the result of
encryption... There is an RFE to change this. Basically allow the DBA to
activate the behavior we have for ANSI databases where we raise an error

5- I think the CHAR vs BYTE length is a non subject... For situation where
we're storing variable length data (names, company names, addresses etc.)
this has always been a guess work... so with UTF8 we need to continue
guessing, but with a bit for uncertainty.... what is the avg. percentage of
2 byte characters in a name? Just accomodate that avg plus a bit more
margin.... Am I wrong?
There will always be times when we notice a defined length was not
enough.... be it bytes or CHARs

Regards

On Tue, Oct 21, 2014 at 4:15 PM, Fernando Nunes <domusonline@gmail.com>
wrote:

> All correct, and expected behavior I would say... SQL_LOGICAL_CHAR acts as
> a multiplier... But you get the byte length in the catalogs.
> DBSchema shows the value you specify.
> Regards
>
> On Tue, Oct 21, 2014 at 2:46 PM, MATTI JAATINEN <matti.jaatinen@norelco.fi
> >
> wrote:
>
> > Appendix for Test case 2:
> >
> > Select length(sar1), length(sar2) from eka;
> > (expression) (expression)
> >
> > 7 7
> >
> > 15 15
> >
> > Select char_length(sar1), char_length(sar2) from eka;
> > (expression) (expression)
> >
> > 14 14
> >
> > 14 14
> >
> > Notice, it should be char_length because length return byte size len and
> > char_length return number of characters(logical characters).
> >
> > When i set onconfig parameter SQL_LOGICAL_CHAR to 3, it tells informix to
> > alloc 3 bytes for 1 character, when creating tables but how informix
> > reports
> > that(column size), IT IS MESSY.
> >
> > So when is exec
> >
> > create table eka
> >
> > (
> >
> > sar1 char(5),
> >
> > sar2 nchar(5)
> >
> > );
> >
> > Informix actually creates table where sar1 is char(15) and sar2
> nchar(15).
> > So
> > next time i do dbschema -d testi -t eka i got
> > create table "informix".eka
> > (
> >
> > sar1 char(5),
> >
> > sar2 nchar(5)
> > );
> >
> > But when i go into dbaccess and check the table eka i got:
> > Column name Type Nulls
> >
> > sar1 char(15) yes
> > sar2 nchar(15) yes
> >
> > or if i check the column size from syscolumns is get 15.
> >
> >
> >
> >
>
> *******************************************************************************
> > Forum Note: Use "Reply" to post a response in the discussion forum.
> >
> >
>
> --
> Fernando Nunes
> Portugal
>
> http://informix-technology.blogspot.com
> My email works... but I don't check it frequently...
>
> --001a113f3756e567030505f04b7f
>
>
>
> *******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>

--
Fernando Nunes
Portugal

http://informix-technology.blogspot.com
My email works... but I don't check it frequently...

--001a11c3634e9575ef0505f0e7df

Messages In This Thread

• Informix 12 Unicode
  MATTI JAATINEN -- Tuesday, 21 October 2014, at 5:34 a.m.
  • Re: Informix 12 Unicode
    MATTI JAATINEN -- Tuesday, 21 October 2014, at 9:16 a.m.
    • Re: Informix 12 Unicode
      MATTI JAATINEN -- Tuesday, 21 October 2014, at 9:46 a.m.
      • Re: Informix 12 Unicode
        Fernando Nunes -- Tuesday, 21 October 2014, at 11:15 a.m.
        • Re: Informix 12 Unicode
          Fernando Nunes -- Tuesday, 21 October 2014, at 11:58 a.m.
          • Re: Informix 12 Unicode
            MATTI JAATINEN -- Wednesday, 22 October 2014, at 1:50 a.m.
            • Re: Informix 12 Unicode
              Martin Fuerderer -- Wednesday, 22 October 2014, at 3:56 a.m.
              • Re: Informix 12 Unicode
                MATTI JAATINEN -- Wednesday, 22 October 2014, at 4:14 a.m.
                • Re: Informix 12 Unicode
                  Martin Fuerderer -- Wednesday, 22 October 2014, at 6:41 a.m.
                  • Re: Informix 12 Unicode
                    Fernando Nunes -- Wednesday, 22 October 2014, at 7:50 a.m.
                    • Re: Informix 12 Unicode
                      Fernando Nunes -- Wednesday, 22 October 2014, at 9:33 a.m.
                  • Re: Informix 12 Unicode
                    Fernando Nunes -- Wednesday, 22 October 2014, at 9:24 a.m.
                    • Re: Informix 12 Unicode
                      MATTI JAATINEN -- Thursday, 23 October 2014, at 1:11 a.m.
            • Re: Informix 12 Unicode
              Fernando Nunes -- Wednesday, 22 October 2014, at 5:30 a.m.
  • Re: Informix 12 Unicode
    Fernando Nunes -- Tuesday, 21 October 2014, at 9:58 a.m.
    • Re: Informix 12 Unicode
      MATTI JAATINEN -- Tuesday, 21 October 2014, at 10:13 a.m.
      • Re: Informix 12 Unicode
        Fernando Nunes -- Tuesday, 21 October 2014, at 11:07 a.m.

IDS Forum is maintained by Administrator with WebBBS 5.12.