[R] sqldf and number of records affected

Ravi Jeyaraman r@v|76 @end|ng |rom gm@||@com
Thu Jun 11 16:06:35 CEST 2020


Thanks for the response Gabor.  Looks like the below example will work when using SQLite, but in my case I'm just creating a dataframe in R and trying to update it using sqldf as below and it doesn't seem to work ...

con <- data.frame(V1 = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
sqldf()
sqldf(c("pragma count_changes = 1", "update con set V1 = 0 where V1 > 5 "))
ans <- sqldf("select * from main.con")
sqldf()

-----Original Message-----
From: Gabor Grothendieck [mailto:ggrothendieck using gmail.com] 
Sent: Thursday, June 11, 2020 9:12 AM
To: Ravi Jeyaraman <ravi76 using gmail.com>
Cc: r-help using r-project.org
Subject: Re: [R] sqldf and number of records affected

Here is an example.  Ignore the warning or use the workaround discussed here
https://github.com/ggrothendieck/sqldf/issues/40
to avoid the warning.

  library(sqldf)
  sqldf()  # use same connection until next sqldf()
  sqldf(c("pragma count_changes = 1", "update BOD set demand = 99 where Time > 4"))
  sqldf("select * from main.BOD")
  sqldf()


On Thu, Jun 11, 2020 at 9:01 AM Ravi Jeyaraman <ravi76 using gmail.com> wrote:
>
> Hello all, When I execute a SQL using SQLDF, how do I get the number 
> of records affected?  I mean, if I run an UPDATE on a data frame, it 
> doesn't tell me if and how many records got updated.  I've read 
> through the documentation and there don't seem to be a way to get this 
> info unless it's done on a database.  Any ideas?
>
> Thanks
> Ravi
>
>
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