
198 Large Scale and Big Data
The idea of triplegroup “matching” a star subpattern in a query has to ensure that
the underlying structure is represented in a triplegroup. For example, triplegroup
tg
3
in Figure 6.5 does not match either of the required star subpatterns since it does
not contain triples with some of the properties required by those subpatterns, for
example, label, product.
In addition, to complete the process, these triplegroups may need to be “joined”
together, for example, using subject-object joins to create the desired subgraph. All
of this essentially implies a data model and algebra for capturing and manipulating
“tripleg