Validate your data model — dm_examine

This function returns a tibble with information about which key constraints are met (is_key = TRUE) or violated (FALSE). The printing for this object is special, use as_tibble() to print as a regular tibble.

Usage

dm_examine_constraints(
  .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:

table: the table in the dm,
kind: "PK" or "FK",
columns: the table columns that define the key,
ref_table: for foreign keys, the referenced table,
is_key: logical,
problem: if is_key = FALSE, the reason for that.

Details

For the primary key constraints, it is tested if the values in the respective columns are all unique. For the foreign key constraints, the tests check if for each foreign key constraint, the values of the foreign key column form a subset of the values of the referenced column.

Examples

dm_nycflights13() %>%
  dm_examine_constraints()
#> ! Unsatisfied constraints:
#> • Table `flights`: foreign key `tailnum` into table `planes`: values of `flights$tailnum` not in `planes$tailnum`: N725MQ (6), N537MQ (5), N722MQ (5), N730MQ (5), N736MQ (5), …