There is a little problem in handling logicals in RMySQL:
# here is the MySQL connection
> con
<MySQLConnection:(1816,0)>
# here is the data frame
> print(a<-data.frame(x=c(TRUE,FALSE),y=c(FALSE,TRUE)))
x y
1 TRUE FALSE
2 FALSE TRUE
# as promised, the two data frame columns are identified as logicals and
# the field types are set to tinyint
> field.types <- sapply(a, dbDataType, dbObj = con)
> field.types
x y
"tinyint" "tinyint"
# However, in WriteTable, nothing is done to convert the logicals to 0s and 1s.
# And logically, the infile is written in TRUE and FALSE and finally, in MySQL
# all becomes zero. Here is what we get in MySQL:
# row_names x y
# 1 0 0
# 2 0 0
#
# So, logically this is what we get back in R:
> dbWriteTable(con,"test",a)
[1] TRUE
> aa<-dbReadTable(con,"test")
> aa
x y
1 0 0
2 0 0
>
# and this is clearly not what we want...
#
# as a crude patch I added for (i in 1:length(value)) if
(class(value[[i]])=="logical") class(value[[i]])<-"integer"
# before i <- match("row.names", ... in mysqlWriteTable
# but others have much more talent in writing clean code than I ...
#
> mysqlWriteTablecrudepatch(con,"test",a,overwrite=TRUE)
[1] TRUE
# and
> aa<-dbReadTable(con,"test")
> aa
x y
1 1 0
2 0 1
# and this IS what we want.
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 1
minor 6.1
year 2002
month 11
day 01
language R
Christian Ritter
Functional Specialist Statistics
Shell Coordination Centre S.A.
Monnet Centre International Laboratory, Avenue Jean Monnet 1, B-1348 Louvain-La-Neuve,
Belgium
Tel: +32 10 477 349 Fax: +32 10 477 219
Email: [EMAIL PROTECTED]
Internet: http://www.shell.com/chemicals
[[alternate HTML version deleted]]
______________________________________________
[EMAIL PROTECTED] mailing list
http://www.stat.math.ethz.ch/mailman/listinfo/r-help
