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

Description Usage Arguments Details Value

View source: R/Sql.R

Description

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

Usage

1
lowLevelQuerySql.ffdf(connection, query = "", datesAsString = FALSE)

Arguments

connection

The connection to the database server.

query

The SQL statement to retrieve the data

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. Null values in the database are converted to NA values in R.

Value

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


OHDSI/DatabaseConnector documentation built on Nov. 16, 2018, 6:20 p.m.