How do I write data from R to PostgreSQL tables with an autoincrementing primary key?

Question

I have a table in a PostgreSQL database that has a BIGSERIAL auto-incrementing primary key. Recreate it using:

CREATE TABLE foo
(
  \"Id\" bigs         


        

Answer 1

From the thread in hrbrmstr's comment, I found a hack to make this work.

In the postgresqlWriteTable in the RPostgreSQL package, you need to replace the line

sql4 <- paste("COPY", postgresqlTableRef(name), "FROM STDIN")

with

sql4 <- paste(
  "COPY ", 
  postgresqlTableRef(name), 
  "(", 
  paste(postgresqlQuoteId(names(value)), collapse = ","), 
  ") FROM STDIN"
)

Note that the quoting of variables (not included in the original hack) is necessary to pass case-sensitive column names.

Here's a script to do that:

body_lines <- deparse(body(RPostgreSQL::postgresqlWriteTable))
new_body_lines <- sub(
  'postgresqlTableRef(name), "FROM STDIN")', 
  'postgresqlTableRef(name), "(", paste(shQuote(names(value)), collapse = ","), ") FROM STDIN")', 
  body_lines,
  fixed = TRUE
)
fn <- RPostgreSQL::postgresqlWriteTable
body(fn) <- parse(text = new_body_lines)
while("RPostgreSQL" %in% search()) detach("package:RPostgreSQL")
assignInNamespace("postgresqlWriteTable", fn, "RPostgreSQL")