dm (version 0.0.6.9000)

dm_get_fk: Retrieve the names of the columns marked as a foreign key, pointing from one table of a dm to another table.

Description

dm_get_fk() returns the names of the columns marked as foreign key of table table with respect to table ref_table within a dm object. If no foreign key is set between the tables, an empty character vector is returned.

Usage

dm_get_fk(dm, table, ref_table)

Arguments

dm

A dm object.

table

A table in the dm.

ref_table

The table that is referenced from table.

Value

A character vector with the column name(s) of table, pointing to the primary key of ref_table.

Compound keys

Currently, keys consisting of more than one column are not supported. This feature is planned for dm 0.2.0. Therefore the function may return vectors of length greater than one in the future.

See Also

Other foreign key functions: dm_add_fk(), dm_enum_fk_candidates(), dm_get_all_fks(), dm_has_fk()

Examples

# NOT RUN {
dm_get_fk(dm_nycflights13(), flights, airports)
# }