odm_read: Query an ODM database

In D-ESC/ODMr: ODM Data Access

Description

The function odm_read can be used to get data from ODM database. ODMselect returns a data frame containing the required columns for working with ODM data.

Usage

odm_read(
  utc_offset = -5,
  site_id = NULL,
  variable_id = NULL,
  qualifier_id = NULL,
  method_id = NULL,
  source_id = NULL,
  level_id = NULL,
  aggregate_by = "day",
  FUN = "mean",
  start_date = NULL,
  end_date = NULL,
  n = 1e+06,
  channel = ODM
)

Arguments

utc_offset	of the observation
site_id	index value for the location at which the observation was made
variable_id	index value for the variable that the data represents
qualifier_id	of the observations you want to extract
method_id	index value for the method used to collect the observation
source_id	the source of the data
level_id	the level of quality control processing
aggregate_by	aggregation level to include in SQL query. Either hour, day, month, year or none
FUN	function to aggregate by. Either min, max, mean, or sum
start_date	access data from this date forward
end_date	access data up to this date
n	maximum number of observations to return
channel	connection handle as returned by odbcConnect

Details

A standard SQL query is issued to the ODM database and the values are returned. The data returned can be limited by a start and/or end date defined by the user. Smaller datasets can speed up the workflow especially when visualising data.

Value

A data frame

Examples

## Not run: 
# Establish connection with database
ODM <- odbc::dbConnect(odbc::odbc(), dsn = "ODM", database = "OD",
 UID = "update", PWD = rstudioapi::askForPassword("Database password"),
 Port = 1433)

# Extract data by site, variable, method and QC level. Clear and consistent
# method to extract data.
Data <- odm_read(site_id = 1, variable_id = 1, method_id = 9,
 level_id = 0, start_date = "2013-06-01",
 end_date = "2013-07-01", channel = ODM)

## End(Not run)

D-ESC/ODMr documentation built on Sept. 16, 2021, 10:52 a.m.