Writing and Updating DB2 tables with r - r

Question

I can't figure out how to update an existing DB2 database in R or update a single value in it.
I can't find much information on this topic online other than very general information, but no specific examples.
library(RJDBC)
teachersalaries=data.frame(name=c("bob"), earnings=c(100))
dbSendUpdate(conn, "UPDATE test1 salary",teachersalaries[1,2])
AND
teachersalaries=data.frame(name=c("bob",'sally'), earnings=c(100,200))
dbSendUpdate(conn, "INSERT INTO test1 salary", teachersalaries[which(teachersalaries$earnings>200,] )

Answer 1

Have you tried passing a regular SQL statement like you would in other languages?
dbSendUpdate(conn, "UPDATE test1 set salary=? where id=?", teachersalary, teacherid)
or
dbSendUpdate(conn,"INSERT INTO test1 VALUES (?,?)",teacherid,teachersalary)
Basically you specify the regular SQL DML statement using parameter markers (those question marks) and provide a list of values as comma-separated parameters.

Answer 2

Try this, it worked for me well.
dbSendUpdate(conn,"INSERT INTO test1 VALUES (?,?)",teacherid,teachersalary)
You just need to pass a regular SQL piece in the same way you do in any programing langs. Try it out.

Answer 3

To update multiple rows at the same time, I have built the following function.
I have tested it with batches of up to 10,000 rows and it works perfectly.
# Libraries
library(RJDBC)
library(dplyr)
# Function upload data into database
db_write_table <- function(conn,table,df){
# Format data to write
batch <- apply(df,1,FUN = function(x) paste0("'",trimws(x),"'", collapse = ",")) %>%
paste0("(",.,")",collapse = ",\n")
#Build query
query <- paste("INSERT INTO", table ,"VALUES", batch)
# Send update
dbSendUpdate(conn, query)
}
# Push data
db_write_table(conn,"schema.mytable",mydataframe)
Thanks to the other authors.