incorporate_foreign_keys: Factorize foreign keys

In QBRC/RODProt: An R Client for Interacting with Data Encoded in one of the 'Open Data Protocols' Standards.

Description

Identify the columns in the table which have been labeled as foreign keys and map them to their proper label based on the underlying level.

Usage

  incorporate_foreign_keys(table, schema,
    name.columns = "name", ...)

Arguments

table	The JSON Table as read in from read_json_table.
schema	The JSON Table Schema associated with this table.
name.columns	the name of the column to use as the levels of the factor. If the referenced table has two of fewer columns, this value will be ignored. See Details for more information.
...	Parameters passed on to get_resource

Details

This function aims to create factors from the columns identified as having a foreign key in the provided schema. In order to do this in R, up to two columns will be involved: the ID columns (as specified in the foreignkey attribute in the schema), and the names or levels to be associated with these values. In the current implementation, these levels will be converted to character vectors.

The behavior is as follows: if there is only one column in the referenced resource and that column matches the ID given for the foreignkey, that column will be used as both the IDs and the levels of the factor – meaning that any values defined in this external table will map to themselves, and any other values not in the table will map to NA. If the table has two columns, one of which matches the ID value of the foreignkey, then the ID column will be used for the IDs, and the second column, regardless of name, will be used as the levels for the factor. If there are more than two columns, then the column to be used as the name must be specified using the name.column parameter.

Author(s)

Jeffrey D. Allen [e-mail]

QBRC/RODProt documentation built on May 8, 2019, 3:11 p.m.