Python API

This is the API documentation for mgp.py which contains definitions of the public Python API provided by Memgraph. In essence, this is a wrapper around the [C API](mg_procedure.md). This source file can be found in the Memgraph installation directory, under python_support. On the standard Debian installation, this will be under /usr/lib/memgraph/python_support.
Contents
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Name
method
​mgp.read_proc 
Register a function as a read-only procedure of the current module.
exception
​mgp.AbortError 
Signals that the procedure was asked to abort its execution.
class
​mgp.Deprecated 
Annotate a resulting Record’s field as deprecated.
class
​mgp.Edge 
Edge in the graph database.
class
​mgp.EdgeType 
Type of an Edge.
class
​mgp.Graph 
State of the graph database in current ProcCtx.
class
​mgp.Label 
Label of a Vertex.
class
​mgp.Path 
Path containing Vertex and Edge instances.
class
​mgp.ProcCtx 
Context of a procedure being executed.
class
​mgp.Properties 
A collection of properties either on a Vertex or an Edge.
class
​mgp.Property 
Named property value of a Vertex or an Edge.
class
​mgp.Record 
Represents a record of resulting field values.
class
​mgp.Vertex 
Vertex in the graph database.
class
​mgp.Vertices 
Iterable over vertices in a graph.
mgp.read_proc(func: Callable[[…], mgp.Record])
Register func as a read-only procedure of the current module.
read_proc is meant to be used as a decorator function to register module procedures. The registered func needs to be a callable which optionally takes ProcCtx as the first argument. Other arguments of func will be bound to values passed in the cypherQuery. The full signature of func needs to be annotated with types. The return type must be Record(field_name=type, ...) and the procedure must produce either a complete Record or None. To mark a field as deprecated, use Record(field_name=Deprecated(type), ...). Multiple records can be produced by returning an iterable of them. Registering generator functions is currently not supported.
exception mgp.AbortError()
Bases: Exception
Signals that the procedure was asked to abort its execution.
class mgp.Deprecated(type_)
Bases: object
Annotate a resulting Record’s field as deprecated.
field_type()
class mgp.Edge(edge)
Bases: object
Edge in the graph database.
Access to an Edge is only valid during a single execution of a procedure in a query. You should not globally store an instance of an Edge. Using an invalid Edge instance will raise InvalidContextError.
property from_vertex()
Raise InvalidContextError.
property id()
Raise InvalidContextError.
is_valid()
Return True if self is in valid context and may be used.
property properties()
Raise InvalidContextError.
property to_vertex()
Raise InvalidContextError.
property type()
Raise InvalidContextError.
class mgp.EdgeType(name)
Bases: object
Type of an Edge.
property name()
class mgp.Graph(graph)
Bases: object
State of the graph database in current ProcCtx.
get_vertex_by_id(vertex_id: NewType..new_type)
Return the Vertex corresponding to given vertex_id from the graph.
Access to a Vertex is only valid during a single execution of a procedure in a query. You should not globally store the returned Vertex.
Raise IndexError if unable to find the given vertex_id. Raise InvalidContextError if context is invalid.
is_valid()
Return True if self is in valid context and may be used.
property vertices()
All vertices in the graph.
Access to a Vertex is only valid during a single execution of a procedure in a query. You should not globally store the returned Vertex instances.
Raise InvalidContextError if context is invalid.
exception mgp.InvalidContextError()
Bases: Exception
Signals using a graph element instance outside of the registered procedure.
class mgp.Label(name)
Bases: object
Label of a Vertex.
property name()
class mgp.Path(starting_vertex_or_path: Union[_mgp.Path, mgp.Vertex])
Bases: object
Path containing Vertex and Edge instances.
property edges()
Edges ordered from the start to the end of the path.
Raise InvalidContextError if using an invalid Path instance.
expand(edge: mgp.Edge)
Append an edge continuing from the last vertex on the path.
The last vertex on the path will become the other endpoint of the given edge, as continued from the current last vertex.
Raise ValueError if the current last vertex in the path is not part of the given edge. Raise InvalidContextError if using an invalid Path instance or if passed in edge is invalid.
is_valid()
property vertices()
Vertices ordered from the start to the end of the path.
Raise InvalidContextError if using an invalid Path instance.
class mgp.ProcCtx(graph)
Bases: object
Context of a procedure being executed.
Access to a ProcCtx is only valid during a single execution of a procedure in a query. You should not globally store a ProcCtx instance.
check_must_abort()
property graph()
Raise InvalidContextError if context is invalid.
is_valid()
must_abort()
class mgp.Properties(vertex_or_edge)
Bases: object
A collection of properties either on a Vertex or an Edge.
get(property_name: str, default=None)
Get the value of a property with the given name or return default.
Raise InvalidContextError.
items()
Raise InvalidContextError.
keys()
Iterate over property names.
Raise InvalidContextError.
values()
Iterate over property values.
Raise InvalidContextError.
class mgp.Property(name, value)
Bases: tuple
Named property value of a Vertex or an Edge.
name()
Alias for field number 0
value()
Alias for field number 1
class mgp.Record(**kwargs)
Bases: object
Represents a record of resulting field values.
fields()
exception mgp.UnsupportedTypingError(type_)
Bases: Exception
Signals a typing annotation is not supported as a _mgp.CypherType.
class mgp.Vertex(vertex)
Bases: object
Vertex in the graph database.
Access to a Vertex is only valid during a single execution of a procedure in a query. You should not globally store an instance of a Vertex. Using an invalid Vertex instance will raise InvalidContextError.
property id()
Raise InvalidContextError.
property in_edges()
Raise InvalidContextError.
is_valid()
Return True if self is in valid context and may be used
property labels()
Raise InvalidContextError.
property out_edges()
Raise InvalidContextError.
property properties()
Raise InvalidContextError.
class mgp.Vertices(graph)
Bases: object
Iterable over vertices in a graph.
is_valid()
Return True if self is in valid context and may be used.

C API

NetworkX

Last updated 3 months ago

	Name
method	mgp.read_proc Register a function as a read-only procedure of the current module.
exception	mgp.AbortError Signals that the procedure was asked to abort its execution.
class	mgp.Deprecated Annotate a resulting Record’s field as deprecated.
class	mgp.Edge Edge in the graph database.
class	mgp.EdgeType Type of an Edge.
class	mgp.Graph State of the graph database in current ProcCtx.
class	mgp.Label Label of a Vertex.
class	mgp.Path Path containing Vertex and Edge instances.
class	mgp.ProcCtx Context of a procedure being executed.
class	mgp.Properties A collection of properties either on a Vertex or an Edge.
class	mgp.Property Named property value of a Vertex or an Edge.
class	mgp.Record Represents a record of resulting field values.
class	mgp.Vertex Vertex in the graph database.
class	mgp.Vertices Iterable over vertices in a graph.