14.7.2 Managing Collections and Scalars
The client can create graph-bound vertex and edge collections to use during the analysis with the following methods in PgxGraph:
VertexSequence<E> createVertexSequence()
VertexSequence<E> createVertexSequence(String name)
VertexSet<E> createVertexSet()
VertexSet<E> createVertexSet(String name)
EdgeSequence createEdgeSequence()
EdgeSequence createEdgeSequence(String name)
EdgeSet createEdgeSet()
EdgeSet createEdgeSet(String name) create_edge_sequence(self, name=None)
create_vertex_sequence(self, name=None)
create_edge_set(self, name=None)
create_edge_sequence(self, name=None)PGX also supports scalar collections such as set and
sequence. Each of these collections can hold elements of
various primitive data types like INTEGER, LONG,
FLOAT, DOUBLE or BOOLEAN.
Scalar collections are session-bound and can be created with the following methods
in PgxSession:
ScalarSet<T> createSet(PropertyType contentType, String name)
ScalarSequence<T> createSequence(PropertyType contentType, String name)
ScalarSet<T> createSet(PropertyType contentType)
ScalarSequence<T> createSequence(PropertyType contentType)In the preceding code, the optional argument (name)
specifies the name of the newly created collection. If omitted, PGX chooses a name
for the client. As with properties, the collections holding vertices are
parametrized with the ID type of the vertices. Refer to graph
configuration chapter to learn how to specify the vertex ID type of a graph.
The return value is the collection object which points to the newly created empty collection.
To drop a collection from the session, call destroy() on
the collection object.
To check which collections are currently allocated for a graph you can use the following method:
Map<String, PgxCollection<? extends PgxEntity<?>, ?>> getCollections()get_collections(self)The returned map contains the names of the collections as keys and the collections as values. The collections can be casted to the matching collection subclass.
PGX supports special Map collection types and allows
users to map between different data types
(oracle.pgx.common.types.PropertyType). Maps can be created
using PgxGraph or PgxSession APIs, the difference
is that the latter supports only non graph-related types, and that the created maps
directly depend on the session:
PgxMap<K, V> createMap(PropertyType keyType, PropertyType valType)
PgxMap<K, V> createMap(PropertyType keyType, PropertyType valType, String mapName)Similarly, scalar variables can be created in the client session using the following methods:
Scalar<T> createScalar(PropertyType type, String newScalarName)
Scalar<T> createScalar(PropertyType type)create_scalar(self,data_type,name=None)These collections and scalar variables can then be passed as arguments to graph algorithms. See Using Custom PGX Graph Algorithms for more information.
Parent topic: Managing Transient Data