[R] Q

Duncan Murdoch murdoch at stats.uwo.ca
Sun Apr 1 14:56:40 CEST 2007

On 4/1/2007 3:39 AM, Prof Brian Ripley wrote:
> I think this is about RODBC, uncredited.
> There is currently no way to do escapes here, and I am pretty sure that 
> ODBC drivers do not support 'slash' as an escape (or did you mean 
> backslash? I am still not sure that would work).
> sqlSave() has fast=TRUE and fast=FALSE options, and it is worth trying 
> both.  Since the default fast=TRUE passes character data as binary fields, 
> I don't understand why there is a problem (there might be for fast=FALSE 
> with single quotes in character fields).

SQL doubles quotes to escape them, doesn't it?  I.e. if I wanted

this 'value'

as an SQL literal, I would use

'this ''value'''

I think this is described in the SQL 92 standard (it defines
<quote symbol> ::= <quote><quote>), but I don't know if it is 
universally implemented.  So if this syntax is supported in Laurent's 
driver/DBMS combination, he could simply double the quotes himself 
before trying to save them, i.e.

values <- gsub("'", "''", values)

Duncan Murdoch

> Without any relevant details (OS, R version, packages used, package 
> version, ODBC driver, DBMS) and any sort of example it is really hard to 
> offer help: please DO study the R posting guide (and note also the comment 
> about using a signature block).
> On Sat, 31 Mar 2007, Laurent Valdes wrote:
>> Hi everybody,
>> I'm doing a sqlSave() in R, to insert a big data frame of 10000 rows.
>> However, there is problems, since several rows contains quotations marks,
>> that can leave inserts buggy.
>> I would like to find a way to add slashes in front of these quotation marks.
>> Best regards,
>> Laurent

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