replyr (version 1.0.5)

topoSortTables: Topologically sort join plan so values are available before uses.

Description

Depends on igraph package. Please see vignette('DependencySorting', package = 'replyr') and vignette('joinController', package= 'replyr') for more details.

Usage

topoSortTables(columnJoinPlan, leftTableName, ...)

Arguments

columnJoinPlan

join plan

leftTableName

which table is left

...

force later arguments to bind by name

Value

list with dependencyGraph and sorted columnJoinPlan

Examples

# NOT RUN {
if (requireNamespace("RSQLite", quietly = TRUE)) {
  # note: employeeanddate is likely built as a cross-product
  #       join of an employee table and set of dates of interest
  #       before getting to the join controller step.  We call
  #       such a table "row control" or "experimental design."
  my_db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
  RSQLite::initExtension(my_db)
  tDesc <- example_employeeAndDate(my_db)
  columnJoinPlan <- buildJoinPlan(tDesc, check= FALSE)
  # unify keys
  columnJoinPlan$resultColumn[columnJoinPlan$resultColumn=='id'] <- 'eid'
  # look at plan defects
  print(paste('problems:',
              inspectDescrAndJoinPlan(tDesc, columnJoinPlan)))
  # fix plan
  if(requireNamespace('igraph', quietly = TRUE)) {
    sorted <- topoSortTables(columnJoinPlan, 'employeeanddate')
    print(paste('problems:',
                inspectDescrAndJoinPlan(tDesc, sorted$columnJoinPlan)))
    # plot(sorted$dependencyGraph)
  }
  DBI::dbDisconnect(my_db)
  my_db <- NULL
}

# }