dbApply: Apply a R function to an external MonetDB table.

In MonetDBLite: In-Process Version of 'MonetDB'

Description

dbApply uses the R UDF facilities in standalone MonetDB to apply the passed function to a table.

Usage

  mdbapply(conn, table, fun, ...)

Arguments

conn	An external MonetDB.R database connection. Created using dbConnect with the MonetDB.R external database driver.
table	An external MonetDB database table. Can also be a view or temporary table.
fun	A R function to be run on the external database table. The function gets passed a single data.frame argument which represents the database table. The function needs to return a single vector (for now).
...	Other parameters to be passed to the function

Value

Returns the result of the function applied to the database table.

Examples

## Not run: 
library(DBI)
con <- dbConnect(MonetDB.R(), "demo")
data(mtcars)
dbWriteTable(con, "mtcars", mtcars)

mpgplus42 <- mdbapply(con, "mtcars", "double", function(d) {
	d$mpg + 42
})

## End(Not run)

MonetDBLite documentation built on July 28, 2018, 1:02 a.m.