R/src-JDBC.r

In chappers/dplyrNetezza: Extends dplyr to use JDBC SQL drivers.

#' @import dplyr
NULL

#' Connect to Netezza database with a Netezza JDBC driver
#' 
#' Use \code{src_JDBC} to connect to Netezza database with JDBC driver.
#' @export
src_JDBC <- function(driver, url = NULL, user = NULL, password = NULL, ...) {
  if (!require("RJDBC")) {
    stop("RJDBC package required to connect to JDBC db", call. = FALSE)
  }

  user <- user %||% ""

  con <- DBI:::dbConnect(driver, url = url %||% "", user = user %||% "",
    password = password %||% "", ...)

  .jcall(con@jc, "V", "setAutoCommit", FALSE)

  info <- list(url=url, user=user, driver=.jstrVal(con@jc))

  src_sql("JDBC", con,
    info = info, disco = dplyr:::db_disconnector(con, "JDBC"))
}

#' @export
#' @rdname src_JDBC
tbl.src_JDBC <- function(src, from, ...) {
  tbl_sql("JDBC", src = src, from = from, ...)
}

#' @export
# TODO: fix for JDBC
brief_desc.src_JDBC <- function(x) {
  info <- x$info
  paste0("JDBC ", info$driver, " [", info$url, "]")
}

#' @export
src_translate_env.src_JDBC <- function(x) {
  sql_variant(
    base_scalar,
    sql_translator(.parent = base_agg,
      n = function() sql("count(*)")
    ),
    base_win
  )
}

# DB backend methods
#' @export
db_list_tables.JDBCConnection <- function(con) {
  DBI::dbListTables(con)
}

#' @export
db_has_table.JDBCConnection <- function(con, table) {
  table %in% db_list_tables(con)
}

#' @export
db_query_fields.JDBCConnection <- function(con, sql, ...)
{
  rs <- dbSendQuery(con, paste0("SELECT * FROM ", sql))
  on.exit(dbClearResult(rs))
  names(fetch(rs, 1L))
}