howto-dm-df.R
In dm: Relational Data Models

## ----setup, include = FALSE----------------------------------------------
source("setup/setup.R")

## ----nycflights13, message=FALSE-----------------------------------------
#  library(nycflights13)
#  
#  airports

## ------------------------------------------------------------------------
#  library(dm)
#  
#  flights_dm_no_keys <- dm(airlines, airports, flights, planes, weather)
#  flights_dm_no_keys

## ----listlike------------------------------------------------------------
#  names(flights_dm_no_keys)
#  flights_dm_no_keys$airports
#  flights_dm_no_keys[c("airports", "flights")]

## ------------------------------------------------------------------------
#  dm_enum_pk_candidates(
#    dm = flights_dm_no_keys,
#    table = planes
#  )

## ------------------------------------------------------------------------
#  flights_dm_only_pks <-
#    flights_dm_no_keys %>%
#    dm_add_pk(table = airlines, columns = carrier) %>%
#    dm_add_pk(airports, faa) %>%
#    dm_add_pk(planes, tailnum) %>%
#    dm_add_pk(weather, c(origin, time_hour))
#  flights_dm_only_pks

## ------------------------------------------------------------------------
#  dm_enum_fk_candidates(
#    dm = flights_dm_only_pks,
#    table = flights,
#    ref_table = airlines
#  )

## ------------------------------------------------------------------------
#  flights_dm_all_keys <-
#    flights_dm_only_pks %>%
#    dm_add_fk(table = flights, columns = tailnum, ref_table = planes) %>%
#    dm_add_fk(flights, carrier, airlines) %>%
#    dm_add_fk(flights, origin, airports) %>%
#    dm_add_fk(flights, c(origin, time_hour), weather)
#  flights_dm_all_keys

## ------------------------------------------------------------------------
#  flights_dm_no_keys %>%
#    dm_draw(rankdir = "TB", view_type = "all")

## ------------------------------------------------------------------------
#  flights_dm_no_keys %>%
#    dm_add_pk(airlines, carrier) %>%
#    dm_draw()

## ------------------------------------------------------------------------
#  flights_dm_only_pks %>%
#    dm_add_fk(flights, tailnum, planes) %>%
#    dm_draw()

## ------------------------------------------------------------------------
#  flights_dm_all_keys %>%
#    dm_draw()

## ------------------------------------------------------------------------
#  flights_dm_no_keys %>%
#    dm_examine_constraints()
#  
#  flights_dm_only_pks %>%
#    dm_examine_constraints()
#  
#  flights_dm_all_keys %>%
#    dm_examine_constraints()

## ------------------------------------------------------------------------
#  flights_dm_only_pks %>%
#    dm_get_all_pks()

## ------------------------------------------------------------------------
#  flights_dm_all_keys %>%
#    dm_get_all_fks()

## ------------------------------------------------------------------------
#  flights_dm_all_keys %>%
#    dm_examine_constraints() %>%
#    tibble::as_tibble()