How to subset monet.frame with %in% properly

Question

It seems everything is ok if

subset(mdf, id %in% c("A","B"))

but error if

ids = c("A","B")
subset(mdf,id %in% ids)

The following is demo codes:

con1 = dbConnect(dbDriver("MonetDB"),"monetdb://go:50000/voc")
d = data.frame(id=base::sample(c("A","B","C","D"),100,replace=T),v=sample(1:10,100,replace=T),stringsAsFactors=F)
head(d)
str(d)

dbWriteTable(con1, "test", d)

mdf <- monet.frame(con1,"test")
subset(mdf, id %in% c("A","B"))

ids = c("A","B")
subset(mdf,id %in% ids)

MonetDB.R_0.8.0 DBI_0.2-7

R version 3.0.2 (2013-09-25) Platform: x86_64-pc-linux-gnu (64-bit)

The subset(mdf, id %in% c("A","B")) actually translate to sql as:

MonetDB-backed data.frame surrogate
2 columns, 44 rows
Query: SELECT * FROM test WHERE ( (id IN ('A','B')) ) 
Columns: id (character), v (numeric)

The error message for IDS = c("A","B") subset(mdf,id %in% IDS)

is something like:

Error in .local(conn, statement, ...) : 
  Unable to execute statement 'SELECT COUNT(*) FROM test WHERE ( (id IN 'AB') ) '.
Server says 'syntax error, unexpected STRING, expecting '(' in: "select count(*) from test where ( (id in 'AB'"' [#42000].

I guess it is a MonetDB.R specific issue. Just don't know how to circumvent it.

Thanks.

Answer 1

First of all, thanks for the very good bug report that was generated by cooperation here. I had encountered this issue sometime before, it should be fixed in version 0.8.1 of the package that is available on R-Forge (https://r-forge.r-project.org/R/?group_id=1534).