Execute an ordered sequence of left joins.

Please see vignette('DependencySorting', package = 'rquery') and vignette('joinController', package= 'rquery') for more details.

actualize_join_plan(
  columnJoinPlan,
  ...,
  jointype = "LEFT",
  add_ind_cols = FALSE,
  checkColClasses = FALSE
)

Arguments

columnJoinPlan	columns to join, from build_join_plan (and likely altered by user). Note: no column names must intersect with names of the form table_CLEANEDTABNAME_present.
...	force later arguments to bind by name.
jointype	character, type of join to perform ("LEFT", "INNER", "RIGHT", ...).
add_ind_cols	logical, if TRUE add indicators showing which tables supplied rows.
checkColClasses	logical if true check for exact class name matches

Value

join optree

See also

describe_tables, build_join_plan, inspect_join_plan, graph_join_plan

Examples

if (requireNamespace("DBI", quietly = TRUE) && requireNamespace("RSQLite", quietly = TRUE)) {
  my_db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
  # example data
  DBI::dbWriteTable(my_db,
                    "meas1",
                    data.frame(id= c(1,2),
                               weight= c(200, 120),
                               height= c(60, 14)))
  DBI::dbWriteTable(my_db,
                    "meas2",
                    data.frame(pid= c(2,3),
                               weight= c(105, 110),
                               width= 1))
  # get the initial description of table defs
  tDesc <- describe_tables(my_db, qc(meas1, meas2))
  # declare keys (and give them consitent names)
  tDesc$keys[[1]] <- list(PatientID= 'id')
  tDesc$keys[[2]] <- list(PatientID= 'pid')
  # build the column join plan
  columnJoinPlan <- build_join_plan(tDesc)
  # decide we don't want the width column
  columnJoinPlan$want[columnJoinPlan$resultColumn=='width'] <- FALSE
  # double check our plan
  if(!is.null(inspect_join_plan(tDesc, columnJoinPlan,
                                checkColClasses= TRUE))) {
    stop("bad join plan")
  }
  # actualize as left join op_tree
  optree <- actualize_join_plan(columnJoinPlan,
                                checkColClasses= TRUE)
  cat(format(optree))
  print(execute(my_db, optree))
  if(requireNamespace("DiagrammeR", quietly = TRUE)) {
    DiagrammeR::grViz(op_diagram(optree))
  }
  DBI::dbDisconnect(my_db)
}
#> mk_td("meas1", c(
#>   "id",
#>   "weight",
#>   "height")) %.>%
#>  rename_columns(.,
#>   c('PatientID' = 'id',
#>     'meas1_weight' = 'weight')) %.>%
#>  natural_join(.,
#>   mk_td("meas2", c(
#>     "pid",
#>     "weight")) %.>%
#>    rename_columns(.,
#>     c('PatientID' = 'pid',
#>       'meas2_weight' = 'weight')),
#>   jointype = "LEFT", by = c('PatientID'))
#>   PatientID meas1_weight height meas2_weight
#> 1         1          200     60           NA
#> 2         2          120     14          105