dbGetInfo function

Metadata about database objects

Metadata about database objects

For the PrestoResult object, the implementation returns the additional stats field which can be used to implement things like progress bars. See the examples section.

## S4 method for signature 'PrestoDriver'
dbGetInfo(dbObj)

## S4 method for signature 'PrestoConnection'
dbGetInfo(dbObj)

## S4 method for signature 'PrestoResult'
dbGetInfo(dbObj)

Arguments

• dbObj: A PrestoDriver , PrestoConnection

  or PrestoResult object

Returns

PrestoResult A list() with elements

• statement: The SQL sent to the database
• row.count: Number of rows fetched so far
• has.completed: Whether all data has been fetched
• stats: Current stats on the query

Examples

## Not run:

conn <- dbConnect(Presto(), "localhost", 7777, "onur", "datascience")
result <- dbSendQuery(conn, "SELECT * FROM jonchang_iris")
iris <- data.frame()
progress.bar <- NULL
while (!dbHasCompleted(result)) {
  chunk <- dbFetch(result)
  if (!NROW(iris)) {
    iris <- chunk
  } else if (NROW(chunk)) {
    iris <- rbind(iris, chunk)
  }
  stats <- dbGetInfo(result)[["stats"]]
  if (is.null(progress.bar)) {
    progress.bar <- txtProgressBar(0, stats[["totalSplits"]], style = 3)
  } else {
    setTxtProgressBar(progress.bar, stats[["completedSplits"]])
  }
}
close(progress.bar)
## End(Not run)