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.

Functions

cassandra.graph.

single_object_row_factory

(column_names, rows)

returns the JSON string value of graph results

cassandra.graph.

graph_result_row_factory

(column_names, rows)

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)

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 as Result.

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 GraphProtocol

Attributes

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 GraphOptions

Options for DSE Graph Query handler.

Attributes

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’)

Methods

set_source_default

()

Sets graph_source to the server-defined default traversal source (‘default’)

set_source_analytics

()

Sets graph_source to the server-defined analytic traversal source (‘a’)

set_source_graph

()

Sets graph_source to the server-defined graph traversal source (‘g’)

class SimpleGraphStatement

Simple graph statement for Session.execute_graph(). Takes the same parameters as SimpleStatement.

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 Result

Represents deserialized graph results. Property and item getters are provided for convenience.

Attributes

value

= None

Deserialized value from the result

Methods

as_vertex

()

Return a Vertex parsed from this result

Raises TypeError if parsing fails (i.e. the result structure is not valid).

as_edge

()

Return a Edge parsed from this result

Raises TypeError if parsing fails (i.e. the result structure is not valid).

as_path

()

Return a Path parsed from this result

Raises TypeError if parsing fails (i.e. the result structure is not valid).

class Vertex

Represents a Vertex element from a graph query.

Vertex properties are extracted into a dict of property names to list of VertexProperty (list because they are always encoded that way, and sometimes have multiple cardinality; VertexProperty because sometimes the properties themselves have property maps).

class VertexProperty

Vertex properties have a top-level value and an optional dict of properties.

Attributes

label

= None

label of the property

value

= None

Value of the property

properties

= None

dict of properties attached to the property

class Edge

Represents an Edge element from a graph query.

Attributes match initializer parameters.

class Path

Represents a graph path.

Labels list is taken verbatim from the results.

Objects are either Result or Vertex/Edge for recognized types

Attributes

labels

= None

List of labels in the path

objects

= None

List of objects in the path

class GraphSON1Serializer

Serialize python objects to graphson types.

class GraphSON1Deserializer

Deserialize graphson1 types to python objects.

Class Methods

classmethod

deserialize_date

(value)
classmethod

deserialize_timestamp

(value)
classmethod

deserialize_time

(value)
classmethod

deserialize_duration

(value)
classmethod

deserialize_int

(value)
classmethod

deserialize_bigint

(value)
classmethod

deserialize_double

(value)
classmethod

deserialize_float

(value)
classmethod

deserialize_uuid

(value)
classmethod

deserialize_blob

(value)
classmethod

deserialize_decimal

(value)
classmethod

deserialize_point

(value)
classmethod

deserialize_linestring

(value)
classmethod

deserialize_polygon

(value)

class GraphSON2Reader

GraphSON2 Reader that parse json and deserialize to python objects.

Parameters

extra_deserializer_map – map from GraphSON type tag to deserializer instance implementing deserialize

Methods

read

(json_data)

Read and deserialize json_data.

deserialize

(obj)

Deserialize GraphSON type-tagged dict values into objects mapped in self.deserializers

class GraphSON3Reader

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