R help - Jun 2020 - sqldf and number of records affected

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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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 at 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
>
>
> --
> This email has been checked for viruses by AVG.
> https://www.avg.com
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.


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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 at gmail.com] 
Sent: Thursday, June 11, 2020 9:12 AM
To: Ravi Jeyaraman <ravi76 at gmail.com>
Cc: r-help at 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 at 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
>
>
> --
> This email has been checked for viruses by AVG.
> https://www.avg.com
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see 
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.


--
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com


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