[R] RODBC: longest string is truncated

[Yeh, Richard C]

Dear Jerome,

Sorry, I'm not running your configuration.  I cannot reproduce this
problem with Sybase Adaptive Server IQ 12.6 and R 2.3.1 + RODBC 1.1.7 on
WinXP SP2 or Linux 2.4.21-32.0.1.ELsmp #1 SMP Tue May 17 17:52:23 EDT
2005 i686 i686 i386 GNU/Linux.

-- ASIQ uses STRING() to mean CONCAT()
-- ASIQ doesn't have the 'TEXT' data type
CREATE TABLE test500
(
        a       VARCHAR(600)	--	explicit length
)
GO
INSERT INTO test500
SELECT STRING(REPEAT('a',499),'1')	-- should be a length-500 string
GO
INSERT INTO test500
SELECT STRING(REPEAT('a',499),'12')
GO
INSERT INTO test500
SELECT STRING(REPEAT('a',499),'123')
GO
SELECT LENGTH(a) FROM test500
-- returns 500, 501, 502

Then, in R (either platform):

> library(RODBC)
> channel = odbcConnect('DSN', believeNRows=FALSE)	#
believeNRows=FALSE required for ASIQ
> b = sqlQuery(channel,"SELECT a FROM test500")
> nchar(as.vector(b[[1]]))
[1] 500 501 502



212-933-3305 / richard.c.yeh at bankofamerica.com 
-----Original Message-----
Subject: [R] RODBC: longest string is truncated
Date: Wed, 04 Oct 2006 17:55:02 -0400
Hello R community:

I'm encountering unexpected behaviour as I download string data from
MySQL using the RODBC package. The unexpected behaviour is that the last
character of the string is truncated. As far as I can see, this happens
when some strings are of length 501 or more.


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