Write ffdf data to a database table by using a DBI connection.

Description

Write ffdf data to a database table by using a DBI connection. This can for example be used to store large ffdf datasets from R in Oracle, SQLite, MySQL, PostgreSQL, Hive or other SQL databases.
Mark that for very large datasets, these SQL databases might have tools to speed up by bulk loading. You might also consider that as an alternative to using this procedure.

Usage

write.dbi.ffdf(x, name, dbConnect.args = list(drv = NULL, dbname = NULL,
  username = "", password = ""), RECORDBYTES = sum(.rambytes[vmode(x)]),
  BATCHBYTES = getOption("ffbatchbytes"), by = NULL, VERBOSE = FALSE, ...)

Arguments

Details

Opens up the DBI connection using DBI::dbConnect, writes data to the SQL table using DBI::dbWriteTable by extracting the data in batches from the ffdf and appending them to the table.

Value

invisible()

See Also

dbWriteTable, chunk

Examples

require(ff)

##
## Example query using data in sqlite
##
require(RSQLite)
dbfile <- system.file("smalldb.sqlite3", package="ETLUtils")
drv <- dbDriver("SQLite")
query <- "select * from testdata limit 10000"
x <- read.dbi.ffdf(query = query, dbConnect.args = list(drv = drv, dbname = dbfile),
first.rows = 100, next.rows = 1000, VERBOSE=TRUE)

write.dbi.ffdf(x = x, name = "helloworld", row.names = FALSE, overwrite = TRUE,
  dbConnect.args = list(drv = drv, dbname = dbfile),
  by = 1000, VERBOSE=TRUE)
test <- read.dbi.ffdf(query = "select * from helloworld",
  dbConnect.args = list(drv = drv, dbname = dbfile))

## Not run: 
require(ROracle)
write.dbi.ffdf(x = x, name = "hellooracle", row.names = FALSE, overwrite = TRUE,
  dbConnect.args = list(drv = dbDriver("Oracle"),
                        user = "YourUser", password = "YourPassword", dbname = "Mydatabase"),
  VERBOSE=TRUE)

## End(Not run)

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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Type 'license()' or 'licence()' for distribution details.

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Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(ETLUtils)
Loading required package: ff
Loading required package: bit
Attaching package bit
package:bit (c) 2008-2012 Jens Oehlschlaegel (GPL-2)
creators: bit bitwhich
coercion: as.logical as.integer as.bit as.bitwhich which
operator: ! & | xor != ==
querying: print length any all min max range sum summary
bit access: length<- [ [<- [[ [[<-
for more help type ?bit

Attaching package: 'bit'

The following object is masked from 'package:base':

    xor

Attaching package ff
- getOption("fftempdir")=="/tmp/RtmpxFPLsO"

- getOption("ffextension")=="ff"

- getOption("ffdrop")==TRUE

- getOption("fffinonexit")==TRUE

- getOption("ffpagesize")==65536

- getOption("ffcaching")=="mmnoflush"  -- consider "ffeachflush" if your system stalls on large writes

- getOption("ffbatchbytes")==16777216 -- consider a different value for tuning your system

- getOption("ffmaxbytes")==536870912 -- consider a different value for tuning your system


Attaching package: 'ff'

The following objects are masked from 'package:bit':

    clone, clone.default, clone.list

The following objects are masked from 'package:utils':

    write.csv, write.csv2

The following objects are masked from 'package:base':

    is.factor, is.ordered

> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/ETLUtils/write.dbi.ffdf.Rd_%03d_medium.png", width=480, height=480)
> ### Name: write.dbi.ffdf
> ### Title: Write ffdf data to a database table by using a DBI connection.
> ### Aliases: write.dbi.ffdf
> 
> ### ** Examples
> 
> require(ff)
> 
> ##
> ## Example query using data in sqlite
> ##
> require(RSQLite)
Loading required package: RSQLite
Loading required package: DBI
> dbfile <- system.file("smalldb.sqlite3", package="ETLUtils")
> drv <- dbDriver("SQLite")
> query <- "select * from testdata limit 10000"
> x <- read.dbi.ffdf(query = query, dbConnect.args = list(drv = drv, dbname = dbfile),
+ first.rows = 100, next.rows = 1000, VERBOSE=TRUE)
read.dbi.ffdf 1..100 (100)  dbi-read=0.002sec ffdf-write=0.015sec
read.dbi.ffdf 101..1100 (1000)  dbi-read=0.002sec ffdf-write=0.006sec
read.dbi.ffdf 1101..2100 (1000)  dbi-read=0.002sec ffdf-write=0.004sec
read.dbi.ffdf 2101..2860 (760)  dbi-read=0.001sec ffdf-write=0.007sec
 dbi-read=0.007sec  ffdf-write=0.032sec  TOTAL=0.039sec
> 
> write.dbi.ffdf(x = x, name = "helloworld", row.names = FALSE, overwrite = TRUE,
+   dbConnect.args = list(drv = drv, dbname = dbfile),
+   by = 1000, VERBOSE=TRUE)
2016-07-04 17:38:11 dbWriteTable chunk 1/3
2016-07-04 17:38:11 dbWriteTable chunk 2/3
2016-07-04 17:38:11 dbWriteTable chunk 3/3
> test <- read.dbi.ffdf(query = "select * from helloworld",
+   dbConnect.args = list(drv = drv, dbname = dbfile))
> 
> ## Not run: 
> ##D require(ROracle)
> ##D write.dbi.ffdf(x = x, name = "hellooracle", row.names = FALSE, overwrite = TRUE,
> ##D   dbConnect.args = list(drv = dbDriver("Oracle"),
> ##D                         user = "YourUser", password = "YourPassword", dbname = "Mydatabase"),
> ##D   VERBOSE=TRUE)
> ## End(Not run)
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>