map_fields_q {cdata}

Map field values from one column into new derived columns (query based, takes name of table).

Description

Map field values from one column into new derived columns (query based, takes name of table).

Usage

map_fields_q(
  dname,
  cname,
  mname,
  my_db,
  rname,
  ...,
  d_qualifiers = NULL,
  m_qualifiers = NULL
)

Arguments

dname

name of table to re-map.

cname

name of column to re-map.

mname

name of table of data describing the mapping (cname column is source, derived columns are destinations).

my_db

database handle.

rname

name of result table.

...

force later arguments to be by name.

d_qualifiers

optional named ordered vector of strings carrying additional db hierarchy terms, such as schema.

m_qualifiers

optional named ordered vector of strings carrying additional db hierarchy terms, such as schema.

Value

re-mapped table

Examples

if (requireNamespace("DBI", quietly = TRUE) &&
  requireNamespace("RSQLite", quietly = TRUE)) {
  my_db <- DBI::dbConnect(RSQLite::SQLite(),
                          ":memory:")
  DBI::dbWriteTable(
    my_db,
    'd',
    data.frame(what = c("acc", "loss",
                        "val_acc", "val_loss"),
               score = c(0.8, 1.2,
                         0.7, 1.7),
               stringsAsFactors = FALSE),
    overwrite = TRUE,
    temporary = TRUE)
  DBI::dbWriteTable(
    my_db,
    'm',
    data.frame(what = c("acc", "loss",
                        "val_acc", "val_loss"),
               measure = c("accuracy", "log-loss",
                           "accuracy", "log-loss"),
               dataset = c("train", "train", "validation", "validation"),
               stringsAsFactors = FALSE),
    overwrite = TRUE,
    temporary = TRUE)

  map_fields_q('d', 'what', 'm', my_db, "dm")
  cdata::qlook(my_db, 'dm')
  DBI::dbDisconnect(my_db)
}