Creates a dm object for the nycflights13 dataSource:
Creates an example
dm object from the tables in nycflights13,
along with the references.
See nycflights13::flights for a description of the data.
As described in nycflights13::planes, the relationship
flights table and the
planes tables is "weak", it does not satisfy
data integrity constraints.
These dots are for future extensions and must be empty.
FALSE(default), only one foreign key relation (from
airports$faa) between the
flightstable and the
airportstable is established. If
dmobject with a double reference between those tables will be produced.
TRUE(default), the resulting
dmobject will have colors assigned to different tables for visualization with
flightstable is reduced to flights with column
dayequal to 10.
FALSE, no link will be established between tables
weather, because this requires compound keys.
dm object consisting of nycflights13 tables, complete with primary and foreign keys and optionally colored.