execute: Execute an operator tree, bringing back the result to memory.

In rquery: Relational Query Generator for Data Manipulation at Scale

Execute an operator tree, bringing back the result to memory.

Description

Run the data query.

Usage

execute(
  source,
  optree,
  ...,
  limit = NULL,
  source_limit = NULL,
  overwrite = TRUE,
  temporary = TRUE,
  allow_executor = TRUE,
  temp_source = mk_tmp_name_source("rquery_ex"),
  env = parent.frame()
)

Arguments

source	data.frame or database connecton (rquery_db_info class or DBI connections preferred).
optree	relop operation tree.
...	force later arguments to bind by name.
limit	numeric, if set limit to this many rows during data bring back (not used when landing a table).
source_limit	numeric if not NULL limit sources to this many rows.
overwrite	logical if TRUE drop an previous table.
temporary	logical if TRUE try to create a temporary table.
allow_executor	logical if TRUE allow any executor set as rquery.rquery_executor to be used.
temp_source	temporary name generator.
env	environment to work in.

Value

data.frame

See Also

materialize, db_td, to_sql, rq_copy_to, mk_td

Examples

# WARNING: example tries to change rquery.rquery_db_executor option to RSQLite and back.
if (requireNamespace("DBI", quietly = TRUE) && requireNamespace("RSQLite", quietly = TRUE)) {
  my_db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
  old_o <- options(list("rquery.rquery_db_executor" = list(db = my_db)))
  d <- rq_copy_to(my_db, 'd',
                   data.frame(AUC = 0.6, R2 = 0.2))
  optree <- extend_se(d, c("v" %:=% "AUC + R2", "x" %:=% "pmax(AUC,v)"))

  print(optree)

  cat(format(optree))

  v <- execute(my_db, optree)
  print(v)

  v2 <- execute(data.frame(AUC = 1, R2 = 2), optree)
  print(v2)

  options(old_o)
  DBI::dbDisconnect(my_db)
}

rquery documentation built on Aug. 20, 2023, 9:06 a.m.