Praveen Kumar Praveen Kumar - 4 years ago 143
R Question

R language unable to insert in postgresql using postgresqlWriteTable

I am new to R and trying to insert R dataframe in Postgresql. Everytime whenever i try to execute my rscripts.R, I am getting the following error:

"In postgresqlWriteTable(conn, name, value, ...) : table customervalidation exists in database: aborting assignTable"

Table customervalidation already exists in postgresql, I am trying to insert the content of SampleData.csv in this table. All the headers of the csv are already present in the table and they are all in lowercase.

Command line argument

./script.R batch SampleData.csv yes no


rscripts.R content

#!/usr/bin/Rscript

options(echo=TRUE) # if you want see commands in output file
args <- commandArgs(trailingOnly = TRUE)
print(args)
# trailingOnly=TRUE means that only your arguments are returned, check:
# print(commandsArgs(trailingOnly=FALSE))

batchIndicator <- tolower(args[1])
filename <- args[2]
isHeaderPresent <-args[3]
isRunTheBatch<-args[4]
rm(args)
#Library files
library(RPostgreSQL)
#now check whether it is immediate or batch.
# if it is immediate then real time prediction needs to prepare.
# if it is batch then whole batch set needs to prepare and keep the results in a separate file.
if(isHeaderPresent == "yes")
{
header = TRUE
}else
{
if(isHeaderPresent == "no"){

header = FALSE
}
}

print(paste("Processing for Batch mode for filename ", filename))
# Start body for other function
data <-read.csv(filename,header = header, sep=",")
drv <- dbDriver("PostgreSQL")
con <- dbConnect(PostgreSQL(), dbname = "customervalidation", host = "localhost", port =5432 , user = "user", password = "pwd")
dbWriteTable(con,"customervalidation",data,row.names=FALSE)
#end body for other function


And content of SampleData.csv
CSV content here

Please help me in identifying the error what is missing here.

Answer Source

The error is rather self-explanatory: The table already exists. If you look at the manual you'll see there are two options:

  • overwrite a logical specifying whether to overwrite an existing table or not. Its default is FALSE.
  • append a logical specifying whether to append to an existing table in the DBMS. Its default is FALSE.

You have to specify one of them as TRUE.

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