Nest a table inside its dm

dm_nest_tbl() converts a child table to a nested column in its parent table. The child table should not have children itself (i.e. it needs to be a terminal child table).

Usage

dm_nest_tbl(dm, child_table, into = NULL)

Arguments

dm

A dm.

child_table

A terminal table with one parent table.

into

The table to nest child_tables into, optional as it can be guessed from the foreign keys unambiguously but useful to be explicit.

See also

dm_wrap_tbl(), dm_unwrap_tbl(), dm_pack_tbl()

Examples

nested_dm <-
  dm_nycflights13() %>%
  dm_select_tbl(airlines, flights) %>%
  dm_nest_tbl(flights)

nested_dm
#> ── Metadata ────────────────────────────────────────────────────────────────────
#> Tables: `airlines`
#> Columns: 3
#> Primary keys: 1
#> Foreign keys: 0

nested_dm$airlines
#> # A tibble: 15 × 3
#>    carrier name                        flights            
#>    <chr>   <chr>                       <nested>           
#>  1 9E      Endeavor Air Inc.           <tibble [104 × 18]>
#>  2 AA      American Airlines Inc.      <tibble [180 × 18]>
#>  3 AS      Alaska Airlines Inc.        <tibble [4 × 18]>  
#>  4 B6      JetBlue Airways             <tibble [296 × 18]>
#>  5 DL      Delta Air Lines Inc.        <tibble [239 × 18]>
#>  6 EV      ExpressJet Airlines Inc.    <tibble [278 × 18]>
#>  7 F9      Frontier Airlines Inc.      <tibble [4 × 18]>  
#>  8 FL      AirTran Airways Corporation <tibble [20 × 18]> 
#>  9 HA      Hawaiian Airlines Inc.      <tibble [2 × 18]>  
#> 10 MQ      Envoy Air                   <tibble [147 × 18]>
#> 11 UA      United Air Lines Inc.       <tibble [294 × 18]>
#> 12 US      US Airways Inc.             <tibble [109 × 18]>
#> 13 VX      Virgin America              <tibble [19 × 18]> 
#> 14 WN      Southwest Airlines Co.      <tibble [62 × 18]> 
#> 15 YV      Mesa Airlines Inc.          <tibble [3 × 18]>