diff options
Diffstat (limited to 'bsfs/triple_store/base.py')
| -rw-r--r-- | bsfs/triple_store/base.py | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/bsfs/triple_store/base.py b/bsfs/triple_store/base.py index 942a16b..6561262 100644 --- a/bsfs/triple_store/base.py +++ b/bsfs/triple_store/base.py @@ -21,7 +21,21 @@ __all__: typing.Sequence[str] = ( ## code ## class TripleStoreBase(abc.ABC): - """ + """TripleStore base class. + + Use the `Open` method to create a new instance and to initialize + the required structures. + + Triple stores express a graph via its (subject, predicate, object) triples. + They provides methods to add and remove triples, and to query the storage + for given graph structures. The subject is always a node in the graph, + whereas nodes are identifiable by a unique URI. Note that blank nodes + (without an explicit URI) are not supported. The object can be another + Node or a Literal value. The relation between a subject and an object + is expressed via a Predicate. The graph structures are governed by a + schema that defines which Node, Literal, and Predicate classes exist + and how they can interact (see `bsfs.schema.Schema`). + """ # storage's URI. None implies a temporary location. @@ -99,9 +113,8 @@ class TripleStoreBase(abc.ABC): self, node_type: _schema.Node, guids: typing.Iterable[URI], - ): - """ - """ + ) -> typing.Iterable[URI]: + """Return those *guids* that exist and have type *node_type* or a subclass thereof.""" @abc.abstractmethod def create( @@ -119,7 +132,17 @@ class TripleStoreBase(abc.ABC): predicate: _schema.Predicate, values: typing.Iterable[typing.Any], ): - """ + """Add triples to the graph. + + It is assumed that all of *guids* exist and have *node_type*. + This method adds a triple (guid, predicate, value) for every guid in + *guids* and each value in *values* (cartesian product). Note that + *values* must have length one for unique predicates, and that + currently existing values will be overwritten in this case. + It also verifies that all symbols are part of the schema and that + the *predicate* matches the *node_type*. + Raises `bsfs.errors.ConsistencyError` if these assumptions are violated. + """ ## EOF ## |