cassandra.graph
- Graph Statements, Options, and Row Factories¶
Note
This module is only for backward compatibility for dse-driver users. Consider using cassandra.datastax.graph.
- cassandra.graph.single_object_row_factory(column_names, rows)[source]¶
returns the JSON string value of graph results
- cassandra.graph.graph_result_row_factory(column_names, rows)[source]¶
Returns a
Result
object that can load graph results and produce specific types. The Result JSON is deserialized and unpacked from the top-level ‘result’ dict.
- cassandra.graph.graph_object_row_factory(column_names, rows)[source]¶
Like
graph_result_row_factory()
, except known element types (Vertex
,Edge
) are converted to their simplified objects. Some low-level metadata is shed in this conversion. Unknown result types are still returned asResult
.
- cassandra.graph.graph_graphson2_row_factory(cluster)¶
Row factory to deserialize GraphSON2 results.
- cassandra.graph.graph_graphson3_row_factory(cluster)¶
Row factory to deserialize GraphSON3 results.
- cassandra.graph.to_int(value)¶
Wraps a value to be explicitly serialized as a graphson Int.
- cassandra.graph.to_bigint(value)¶
Wraps a value to be explicitly serialized as a graphson Bigint.
- cassandra.graph.to_smallint(value)¶
Wraps a value to be explicitly serialized as a graphson Smallint.
- cassandra.graph.to_float(value)¶
Wraps a value to be explicitly serialized as a graphson Float.
- cassandra.graph.to_double(value)¶
Wraps a value to be explicitly serialized as a graphson Double.
- class cassandra.graph.GraphProtocol[source]¶
- GRAPHSON_1_0 = b'graphson-1.0'¶
GraphSON1
- GRAPHSON_2_0 = b'graphson-2.0'¶
GraphSON2
- GRAPHSON_3_0 = b'graphson-3.0'¶
GraphSON3
- class cassandra.graph.GraphOptions(**kwargs)[source]¶
Options for DSE Graph Query handler.
- graph_name¶
name of the targeted graph.
- graph_source¶
choose the graph traversal source, configured on the server side.
- graph_language¶
the language used in the queries (default “gremlin-groovy”)
- graph_read_consistency_level¶
read cassandra.ConsistencyLevel for graph queries (if distinct from session default). Setting this overrides the native Statement.consistency_level for read operations from Cassandra persistence
- graph_write_consistency_level¶
write cassandra.ConsistencyLevel for graph queries (if distinct from session default). Setting this overrides the native Statement.consistency_level for write operations to Cassandra persistence.
- is_default_source¶
- is_analytics_source¶
True if
graph_source
is set to the server-defined analytics traversal source (‘a’)
- is_graph_source¶
True if
graph_source
is set to the server-defined graph traversal source (‘g’)
- set_source_default()[source]¶
Sets
graph_source
to the server-defined default traversal source (‘default’)
- class cassandra.graph.SimpleGraphStatement(query_string, retry_policy=None, consistency_level=None, routing_key=None, serial_consistency_level=None, fetch_size=<object object>, keyspace=None, custom_payload=None, is_idempotent=False)[source]¶
Simple graph statement for
Session.execute_graph()
. Takes the same parameters asSimpleStatement
.query_string should be a literal CQL statement with the exception of parameter placeholders that will be filled through the parameters argument of
Session.execute()
.See
Statement
attributes for a description of the other parameters.
- class cassandra.graph.Result(value)[source]¶
Represents deserialized graph results. Property and item getters are provided for convenience.
- value = None¶
Deserialized value from the result
- as_vertex()[source]¶
Return a
Vertex
parsed from this resultRaises TypeError if parsing fails (i.e. the result structure is not valid).
- class cassandra.graph.Vertex(id, label, type, properties)[source]¶
Represents a Vertex element from a graph query.
Vertex
properties
are extracted into adict
of property names to list ofVertexProperty
(list because they are always encoded that way, and sometimes have multiple cardinality; VertexProperty because sometimes the properties themselves have property maps).
- class cassandra.graph.VertexProperty(label, value, properties=None)[source]¶
Vertex properties have a top-level value and an optional
dict
of properties.- label = None¶
label of the property
- value = None¶
Value of the property
- properties = None¶
dict of properties attached to the property
- class cassandra.graph.Edge(id, label, type, properties, inV, inVLabel, outV, outVLabel)[source]¶
Represents an Edge element from a graph query.
Attributes match initializer parameters.
- class cassandra.graph.Path(labels, objects)[source]¶
Represents a graph path.
Labels list is taken verbatim from the results.
Objects are either
Result
orVertex
/Edge
for recognized types- labels = None¶
List of labels in the path
- objects = None¶
List of objects in the path
- class cassandra.graph.GraphSON1Deserializer[source]¶
Deserialize graphson1 types to python objects.
- classmethod deserialize_float(value)¶
- class cassandra.graph.GraphSON2Reader(context, extra_deserializer_map=None)[source]¶
GraphSON2 Reader that parse json and deserialize to python objects.
- Parameters
extra_deserializer_map – map from GraphSON type tag to deserializer instance implementing deserialize
- class cassandra.graph.GraphSON3Reader(context, extra_deserializer_map=None)[source]¶
GraphSON3 Reader that parse json and deserialize to python objects.
- Parameters
context – A dict of the context, mostly used as context for udt deserialization.
extra_deserializer_map – map from GraphSON type tag to deserializer instance implementing deserialize