lowLevelQuerySql.ffdf: Low level function for retrieving data to an ffdf object

In hxia/DatabaseConnector4Impala: A Wrapper Around RJDBC Containing Drivers for Various DBMSs

Description

This is the equivalent of the querySql.ffdf function, except no error report is written when an error occurs.

Usage

lowLevelQuerySql.ffdf(connection, query = "", batchSize = 5e+05,
  datesAsString = FALSE)

Arguments

connection	The connection to the database server.
query	The SQL statement to retrieve the data
batchSize	The number of rows that will be retrieved at a time from the server. A larger batchSize means less calls to the server so better performance, but too large a batchSize could lead to out-of-memory errors.
datesAsString	Should dates be imported as character vectors, our should they be converted to R's date format?

Details

Retrieves data from the database server and stores it in an ffdf object. This allows very large data sets to be retrieved without running out of memory.

Value

A ffdf object containing the data. If there are 0 rows, a regular data frame is returned instead (ffdf cannot have 0 rows)

hxia/DatabaseConnector4Impala documentation built on May 17, 2019, 9:15 p.m.