Mashup-class: Mashup -- A class for combining Xdata objects
Description
This class administers a list of Xdata objects and
delegates query and scrape and other
methods to them. The aim of the class is to support the
operation of combining different data sources into one
data object.Details
Instances of this class also maintain a database
connection for storing/ collecting data. The database
connection is shared among the administered Xdata
instances.
It is possible to suppress scrape operation by
setting the slot read.only=TRUE. This is useful if
the database is part of a package and is not to be
altered (except for package updates).
Usually it is not necessary for inherited classes to
redefine the queries, scrape or scrapes
methods. Rather, it is recommended to add query
methods with new signatures in the resource slot.