Learn about your data model

This function returns a tibble with information about the cardinality of the FK constraints. The printing for this object is special, use tibble::as_tibble() to print as a regular tibble.

Usage

dm_examine_cardinalities(
  .dm,
  ...,
  .progress = NA,
  dm = deprecated(),
  progress = deprecated()
)

Arguments

.dm

A dm object.

...

These dots are for future extensions and must be empty.

.progress

Whether to display a progress bar, if NA (the default) hide in non-interactive mode, show in interactive mode. Requires the 'progress' package.

dm, progress

Value

A tibble with the following columns:

child_table

child table,

child_fk_cols

foreign key column(s) in child table as list of character vectors,

parent_table

parent table,

parent_key_cols

key column(s) in parent table as list of character vectors,

cardinality

the nature of cardinality along the foreign key.

Details

Uses examine_cardinality() on each foreign key that is defined in the dm.

See also

Other cardinality functions: examine_cardinality()

Examples

dm_nycflights13() %>%
  dm_examine_cardinalities()
#> • FK: flights$(`carrier`) -> airlines$(`carrier`): surjective mapping (child: 1 to n -> parent: 1)
#> • FK: flights$(`origin`) -> airports$(`faa`): generic mapping (child: 0 to n -> parent: 1)
#> • FK: flights$(`origin`, `time_hour`) -> weather$(`origin`, `time_hour`): generic mapping (child: 0 to n -> parent: 1)
#> • FK: flights$(`tailnum`) -> planes$(`tailnum`): Column (`tailnum`) of table `flights` not a subset of column (`tailnum`) of table `planes`.
#> ! Not all FK constraints satisfied, call `dm_examine_constraints()` for details.