Remove relations not linked to the main relations

Filters an object's relations, keeping only the main relations, and those considered ancestors via foreign key references. Foreign key references involving removed relations are also removed.

Usage

reduce(x, ...)

Arguments

x

An object whose relations are to be filtered.

...

further arguments passed to or from other methods.

Value

An object of the same class as x, with the auxiliary relations and foreign key references removed.

Details

Details on how the main tables are chosen are given in individual methods.

This function is mostly intended for simplifying a database, or a database schema, for the purposes of exploration, particularly by examining plots. While the filtering might remove important auxiliary relations, it's also likely to remove any based on spurious dependencies, of which some databases can contain many.

See also

reduce.database_schema, reduce.database.