Обсуждение: Varchar and varchar2

I've looked through the documentation, but I can't find the size of the
limit of varchar...?

All I found was in the User's Guide:

Character Type        Storage        Description
---------------------------------------------------
varchar(n)        (4+n) bytes    variable length with limit
---------------------------------------------------

What does 4+n bytes mean?  And what is the limit?

 Anyone? And is there support for varchar2?

Thanx.

HELP!

Alphabetical sorting... is it broken or is this intentional.  If this is
not a "feature" anyone have any idea of how to actually sort
alphabetically on a text field?

cmj=> create table test (test text);
CREATE
cmj=> insert into test values ('a');
INSERT 240009 1
cmj=> insert into test values ('A');
INSERT 240010 1
cmj=> insert into test values ('ABLE');
INSERT 240011 1
cmj=> insert into test values ('Able');
INSERT 240012 1
cmj=> insert into test values ('AXIOM');
INSERT 240013 1
select * from test order by test;
test
-----
A
ABLE
AXIOM
Able
a
(5 rows)


Thanks!
Chris

Chris,

a and A are have different acsii codes

try:

select test from test order by lower(test)

This should give you what you want.

- Paul

> HELP!
>
> Alphabetical sorting... is it broken or is this intentional.  If this is
> not a "feature" anyone have any idea of how to actually sort
> alphabetically on a text field?
>
> cmj=> create table test (test text);
> CREATE
> cmj=> insert into test values ('a');
> INSERT 240009 1
> cmj=> insert into test values ('A');
> INSERT 240010 1
> cmj=> insert into test values ('ABLE');
> INSERT 240011 1
> cmj=> insert into test values ('Able');
> INSERT 240012 1
> cmj=> insert into test values ('AXIOM');
> INSERT 240013 1
> select * from test order by test;
> test
> -----
> A
> ABLE
> AXIOM
> Able
> a
> (5 rows)
>
>
> Thanks!
> Chris
>
>
>
>

> I've looked through the documentation, but I can't find the size of the
> limit of varchar...?
>
> All I found was in the User's Guide:
>
> Character Type          Storage         Description
> ---------------------------------------------------
> varchar(n)              (4+n) bytes     variable length with limit
> ---------------------------------------------------
>
> What does 4+n bytes mean?  And what is the limit?
>

It means that the minimem length will be 5 bytes and the maximum is the
maximum amount of characters that can be contained in a record
(aproximately 8000 bytes), where 4 bytes are most likely used to contain
the actual number of characters.  n, in the above expression most likely
represents the number of characters to be stored for a particular
instantition of this field.

>  Anyone? And is there support for varchar2?
>

What is varchar2?

...james

I don't know if the code given in the reply (THANK YOU PAUL!!!!) works for
6.3.2 (I'm downloading now to test it), but it failed in 6.3 with the
error 'ERROR:  parser: parse error at or near "("' - but it put me on the
right track.

I wound up using the following:
   select test, lower(test) as ltest from testtable order by ltest;

which *almost* gets it, but is close enough for me...

test |ltest
-----+-----
a    |a
A    |a
ABLE |able
Able |able
AXIOM|axiom

- notice that 'a' and 'A' are reversed... there was a 50/50 shot at it
being perfect, but that will happen in so few cases as to be irrelevant
(hopefully nobody will notice ;-)

Thanks all!

Chris

On Mon, 6 Jul 1998, Paul Mullen wrote:

> Chris,
>
> a and A are have different acsii codes
>
> try:
>
> select test from test order by lower(test)
>
> This should give you what you want.
>
> - Paul
>
> > HELP!
> >
> > Alphabetical sorting... is it broken or is this intentional.  If this is
> > not a "feature" anyone have any idea of how to actually sort
> > alphabetically on a text field?
> >
> > cmj=> create table test (test text);
> > CREATE
> > cmj=> insert into test values ('a');
> > INSERT 240009 1
> > cmj=> insert into test values ('A');
> > INSERT 240010 1
> > cmj=> insert into test values ('ABLE');
> > INSERT 240011 1
> > cmj=> insert into test values ('Able');
> > INSERT 240012 1
> > cmj=> insert into test values ('AXIOM');
> > INSERT 240013 1
> > select * from test order by test;
> > test
> > -----
> > A
> > ABLE
> > AXIOM
> > Able
> > a
> > (5 rows)
> >
> >
> > Thanks!
> > Chris
> >
> >
> >
> >
>
>

I am a psql beginner and am using the libpq++ library to write a series of
programs that access a database.

My database is working well, my problem is with:
PgCursor::Declare

PgCursor CourseData(data, "Student_course_record_portal");

I create this cursor and am able to successfully do:
CourseData.Declare(course_query.c_str())
CourseData.Fetch()
CourseData.GetValue(i, course_fnum)

It is when I want to repeat this process that I have problems.

I want to Declare a different string for the same PgCursor.
and then fetch from this new string's value (a select stmt)

If I just do one or the other things work correctly, but the repeating of
Declare and Fetch cause:
NOTICE:  (transaction aborted): queries ignored until END
which then leads to the Fetch not working.....

I have also tried to just create a different PgCursor -
but this leads to an error
about not being in the default state.

Does anyone know of a fix - or am I making a stupid mistake?

Thank you for your time,
Summer

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