Custom query modules
Rust
Rust API

Query modules Rust API

This is the API documentation for the Rust binding of Memgraph's C API, which contains declarations of all functions for implementing query module procedures and functions. The source files can be found in the Memgraph MAGE file structure (in the memgraph-mage-dev Docker images, they can be found under /mage/rust). On Github, it can be found under the rust file structure (opens in a new tab).

To see how to implement query modules in C++, take a look at the example we provided.

Functions and procedures

Memgraph Procedure API

Memgraph

new

Creates a new Memgraph object.

pub fn new(
    args: *mut mgp_list,
    graph: *mut mgp_graph,
    result: *mut mgp_result,
    memory: *mut mgp_memory,
    module: *mut mgp_module
) -> Memgraph
  • Parameters:
    • args: A pointer to mgp_list.
    • graph: A pointer to mgp_graph.
    • result: A pointer to mgp_result.
    • memory: A pointer to mgp_memory.
    • module: A pointer to mgp_module.
  • Returns: A new instance of Memgraph.
new_default

Creates a new Memgraph object with all underlying data set to null. Used for testing purposes.

#[cfg(test)]
pub(crate) fn new_default() -> Memgraph
  • Returns: A new instance of Memgraph with default values.
args

Returns the arguments passed to the procedure call.

pub fn args(&self) -> Result<List>
  • Returns: A Result containing the List of arguments if successful.
args_ptr

Returns a pointer to the object with all arguments passed to the procedure call.

pub(crate) fn args_ptr(&self) -> *mut mgp_list
  • Returns: A pointer to mgp_list.
graph_ptr

Returns a pointer to the object with graph data.

pub(crate) fn graph_ptr(&self) -> *mut mgp_graph
  • Returns: A pointer to mgp_graph.
result_ptr

Returns a pointer to the object where results could be stored.

pub(crate) fn result_ptr(&self) -> *mut mgp_result
  • Returns: A pointer to mgp_result.
memory_ptr

Returns a pointer to the memory object for advanced memory control.

pub(crate) fn memory_ptr(&self) -> *mut mgp_memory
  • Returns: A pointer to mgp_memory.
module_ptr

Returns a pointer to the module object.

pub fn module_ptr(&self) -> *mut mgp_module
  • Returns: A pointer to mgp_module.
vertices_iter

Returns an iterator over the vertices in the graph.

pub fn vertices_iter(&self) -> Result<VerticesIterator>
  • Returns: A Result containing a VerticesIterator if successful.
vertex_by_id

Returns a vertex with the given ID.

pub fn vertex_by_id(&self, id: i64) -> Result<Vertex>
  • Parameters:
    • id: The ID of the vertex to retrieve.
  • Returns: A Result containing the Vertex if successful.
result_record

Creates a new result record.

pub fn result_record(&self) -> Result<ResultRecord>
  • Returns: A Result containing a new ResultRecord if successful.
add_read_procedure

Registers a new read procedure.

pub fn add_read_procedure(
    &self,
    proc_ptr: extern "C" fn(*mut mgp_list, *mut mgp_graph, *mut mgp_result, *mut mgp_memory),
    name: &CStr,
    required_arg_types: &[NamedType],
    optional_arg_types: &[OptionalNamedType],
    result_field_types: &[NamedType]
) -> Result<()>
  • Parameters:
    • proc_ptr: Identifier of the top-level C function that represents the procedure.
    • name: A string that will be registered as a procedure name inside the Memgraph instance.
    • required_arg_types: An array of all NamedTypes, each one defined by name and an array of Types.
    • optional_arg_types: An array of all OptionalNamedTypes, each one defined by name, an array of Types, and default value.
    • result_field_types: An array of all NamedTypes, each one defined by name and an array of Types.
  • Returns: A Result indicating success or failure.
must_abort

Returns true if the currently executing procedure should abort as soon as possible.

pub fn must_abort(&self) -> bool
  • Returns: true if the procedure should abort, false otherwise.

MgpError

Defines various errors that can occur in the API.

#[derive(Debug, PartialEq)]
pub enum MgpError {
    UnknownError,
    UnableToAllocate,
    InsufficientError,
    OutOfRange,
    LogicError,
    DeletedObject,
    InvalidArgument,
    KeyAlreadyExists,
    ImmutableObject,
    ValueConversion,
    SerializationError,
}

MgpDefault

A trait to define default values for various types.

pub(crate) trait MgpDefault {
    fn default() -> Self;
}

to_rust_mgp_error

Converts a mgp_error to an MgpError.

pub(crate) fn to_rust_mgp_error(error: mgp_error) -> Option<MgpError>
  • Parameters:
    • error: A mgp_error.
  • Returns: An Option containing an MgpError if the error is not MGP_ERROR_NO_ERROR.

invoke_mgp_func

A macro to invoke a Memgraph function and handle the result.

macro_rules! invoke_mgp_func {
    ($result_type:ty, $func:expr) => {{ ... }};
    ($result_type:ty, $func:expr, $($args:expr),+) => {{ ... }};
}

invoke_void_mgp_func

A macro to invoke a Memgraph function that returns void and handle the result.

macro_rules! invoke_void_mgp_func {
    ($func:expr, $($args:expr),+) => {{ ... }};
}

invoke_mgp_func_with_res

A macro to invoke a Memgraph function and map the result to a custom error.

macro_rules! invoke_mgp_func_with_res {
    ($result_type:ty, $err:expr, $func:expr) => {{ ... }};
    ($result_type:ty, $err:expr, $func:expr, $($args:expr),+) => {{ ... }};
}

invoke_void_mgp_func_with_res

A macro to invoke a Memgraph function that returns void and map the result to a custom error.

macro_rules! invoke_void_mgp_func_with_res {
    ($err:expr, $func:expr, $($args:expr),+) => {{ ... }};
}

resolve_mgp_type

Combines the given array of types from left to right to construct mgp_type.

fn resolve_mgp_type(types: &[Type]) -> *mut mgp_type
  • Parameters:
    • types: A slice of Types.
  • Returns: A pointer to the constructed mgp_type.

Graph API

VerticesIterator

new

Creates a new VerticesIterator.

pub(crate) fn new(ptr: *mut mgp_vertices_iterator, memgraph: &Memgraph) -> VerticesIterator
  • Parameters:
    • ptr: A pointer to mgp_vertices_iterator.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of VerticesIterator.
next

Returns the next vertex in the iteration.

fn next(&mut self) -> Option<Vertex>
  • Returns: An Option containing the next Vertex if available, otherwise None.
Drop

Drops the VerticesIterator and releases the associated resources.

fn drop(&mut self)

Vertex

new

Creates a new Vertex.

pub(crate) fn new(ptr: *mut mgp_vertex, memgraph: &Memgraph) -> Vertex
  • Parameters:
    • ptr: A pointer to mgp_vertex.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of Vertex.
mgp_copy

Creates a new Vertex based on an mgp_vertex.

pub(crate) unsafe fn mgp_copy(mgp_vertex: *mut mgp_vertex, memgraph: &Memgraph) -> Result<Vertex>
  • Parameters:
    • mgp_vertex: A pointer to mgp_vertex.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new Vertex instance if successful.
mgp_ptr

Returns the underlying mgp_vertex pointer.

pub(crate) fn mgp_ptr(&self) -> *mut mgp_vertex
  • Returns: A pointer to mgp_vertex.
set_mgp_ptr

Sets a new mgp_vertex pointer.

pub(crate) fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_vertex)
  • Parameters:
    • new_ptr: A new pointer to mgp_vertex.
id

Returns the ID of the Vertex.

pub fn id(&self) -> i64
  • Returns: The ID of the Vertex.
labels_count

Returns the number of labels associated with the Vertex.

pub fn labels_count(&self) -> Result<u64>
  • Returns: A Result containing the number of labels as u64 if successful.
label_at

Returns the label at the specified index.

pub fn label_at(&self, index: u64) -> Result<CString>
  • Parameters:
    • index: The index of the label.
  • Returns: A Result containing the label as a CString if successful.
has_label

Checks if the Vertex has the specified label.

pub fn has_label(&self, name: &CStr) -> Result<bool>
  • Parameters:
    • name: The name of the label as a CStr.
  • Returns: A Result containing true if the Vertex has the label, otherwise false.
property

Returns the value of a property of the Vertex.

pub fn property(&self, name: &CStr) -> Result<Property>
  • Parameters:
    • name: The name of the property as a CStr.
  • Returns: A Result containing the Property if successful.
properties

Returns an iterator over the properties of the Vertex.

pub fn properties(&self) -> Result<PropertiesIterator>
  • Returns: A Result containing a PropertiesIterator if successful.
in_edges

Returns an iterator over the incoming edges of the Vertex.

pub fn in_edges(&self) -> Result<EdgesIterator>
  • Returns: A Result containing an EdgesIterator if successful.
out_edges

Returns an iterator over the outgoing edges of the Vertex.

pub fn out_edges(&self) -> Result<EdgesIterator>
  • Returns: A Result containing an EdgesIterator if successful.
Drop

Drops the Vertex and releases the associated resources.

fn drop(&mut self)

EdgesIterator

new

Creates a new EdgesIterator.

pub(crate) fn new(ptr: *mut mgp_edges_iterator, memgraph: &Memgraph) -> EdgesIterator
  • Parameters:
    • ptr: A pointer to mgp_edges_iterator.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of EdgesIterator.
next

Returns the next edge in the iteration.

fn next(&mut self) -> Option<Edge>
  • Returns: An Option containing the next Edge if available, otherwise None.
Drop

Drops the EdgesIterator and releases the associated resources.

fn drop(&mut self)

Edge

new

Creates a new Edge.

pub(crate) fn new(ptr: *mut mgp_edge, memgraph: &Memgraph) -> Edge
  • Parameters:
    • ptr: A pointer to mgp_edge.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of Edge.
mgp_copy

Creates a new Edge based on an mgp_edge.

pub(crate) unsafe fn mgp_copy(ptr: *mut mgp_edge, memgraph: &Memgraph) -> Result<Edge>
  • Parameters:
    • ptr: A pointer to mgp_edge.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new Edge instance if successful.
mgp_ptr

Returns the underlying mgp_edge pointer.

pub(crate) fn mgp_ptr(&self) -> *mut mgp_edge
  • Returns: A pointer to mgp_edge.
set_mgp_ptr

Sets a new mgp_edge pointer.

pub(crate) fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_edge)
  • Parameters:
    • new_ptr: A new pointer to mgp_edge.
copy

Creates a copy of the Edge.

pub fn copy(&self) -> Result<Edge>
  • Returns: A Result containing the copied Edge if successful.
id

Returns the ID of the Edge.

pub fn id(&self) -> i64
  • Returns: The ID of the Edge.
edge_type

Returns the type of the Edge.

pub fn edge_type(&self) -> Result<CString>
  • Returns: A Result containing the type of the Edge as a CString if successful.
from_vertex

Returns the vertex from which the Edge originates.

pub fn from_vertex(&self) -> Result<Vertex>
  • Returns: A Result containing the originating Vertex if successful.
to_vertex

Returns the vertex to which the Edge points.

pub fn to_vertex(&self) -> Result<Vertex>
  • Returns: A Result containing the destination Vertex if successful.
property

Returns the value of a property of the Edge.

pub fn property(&self, name: &CStr) -> Result<Property>
  • Parameters:
    • name: The name of the property as a CStr.
  • Returns: A Result containing the Property if successful.
properties

Returns an iterator over the properties of the Edge.

pub fn properties(&self) -> Result<PropertiesIterator>
  • Returns: A Result containing a PropertiesIterator if successful.
Drop

Drops the Edge and releases the associated resources.

fn drop(&mut self)

List

new

Creates a new List.

pub(crate) fn new(ptr: *mut mgp_list, memgraph: &Memgraph) -> List
  • Parameters:
    • ptr: A pointer to mgp_list.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of List.
make_empty

Creates an empty List with the specified capacity.

pub fn make_empty(capacity: u64, memgraph: &Memgraph) -> Result<List>
  • Parameters:
    • capacity: The initial capacity of the list.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new List if successful.
mgp_copy

Creates a copy of an existing List.

pub(crate) unsafe fn mgp_copy(ptr: *mut mgp_list, memgraph: &Memgraph) -> Result<List>
  • Parameters:
    • ptr: A pointer to mgp_list.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a copied List if successful.
copy

Creates a copy of the current List.

pub fn copy(&self) -> Result<List>
  • Returns: A Result containing the copied List if successful.
append

Appends a value to the List. Returns an error if there is no space.

pub fn append(&self, value: &Value) -> Result<()>
  • Parameters:
    • value: The Value to append.
  • Returns: A Result indicating success or failure.
append_extend

Appends a value to the List, extending the capacity if necessary.

pub fn append_extend(&self, value: &Value) -> Result<()>
  • Parameters:
    • value: The Value to append.
  • Returns: A Result indicating success or failure.
size

Returns the size of the List.

pub fn size(&self) -> u64
  • Returns: The size of the List.
capacity

Returns the capacity of the List.

pub fn capacity(&self) -> u64
  • Returns: The capacity of the List.
value_at

Returns the value at the specified index.

pub fn value_at(&self, index: u64) -> Result<Value>
  • Parameters:
    • index: The index of the value to retrieve.
  • Returns: A Result containing the Value if successful.
iter

Returns an iterator over the List.

pub fn iter(&self) -> Result<ListIterator>
  • Returns: A Result containing a ListIterator if successful.
mgp_ptr

Returns the underlying mgp_list pointer.

pub(crate) fn mgp_ptr(&self) -> *mut mgp_list
  • Returns: A pointer to mgp_list.
set_mgp_ptr

Sets a new mgp_list pointer.

pub(crate) fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_list)
  • Parameters:
    • new_ptr: A new pointer to mgp_list.
Drop

Drops the List and releases the associated resources.

fn drop(&mut self)

ListIterator

next

Returns the next value in the iteration.

fn next(&mut self) -> Option<Value>
  • Returns: An Option containing the next Value if available, otherwise None.

Map

new

Creates a new Map.

pub(crate) fn new(ptr: *mut mgp_map, memgraph: &Memgraph) -> Map
  • Parameters:
    • ptr: A pointer to mgp_map.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of Map.
mgp_copy

Creates a copy of an existing Map.

pub(crate) unsafe fn mgp_copy(ptr: *mut mgp_map, memgraph: &Memgraph) -> Result<Map>
  • Parameters:
    • ptr: A pointer to mgp_map.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a copied Map if successful.
make_empty

Creates an empty Map.

pub fn make_empty(memgraph: &Memgraph) -> Result<Map>
  • Parameters:
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new empty Map if successful.
insert

Inserts a key-value pair into the Map.

pub fn insert(&self, key: &CStr, value: &Value) -> Result<()>
  • Parameters:
    • key: The key as a CStr.
    • value: The value to insert.
  • Returns: A Result indicating success or failure.
size

Returns the size of the Map.

pub fn size(&self) -> u64
  • Returns: The size of the Map.
at

Returns the value associated with the specified key.

pub fn at(&self, key: &CStr) -> Result<Value>
  • Parameters:
    • key: The key as a CStr.
  • Returns: A Result containing the Value if successful.
iter

Returns an iterator over the Map.

pub fn iter(&self) -> Result<MapIterator>
  • Returns: A Result containing a MapIterator if successful.
mgp_ptr

Returns the underlying mgp_map pointer.

pub(crate) fn mgp_ptr(&self) -> *mut mgp_map
  • Returns: A pointer to mgp_map.
set_mgp_ptr

Sets a new mgp_map pointer.

pub(crate) fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_map)
  • Parameters:
    • new_ptr: A new pointer to mgp_map.
Drop

Drops the Map and releases the associated resources.

fn drop(&mut self)

MapItem

Fields

Represents an item in the Map with a key-value pair.

  • key: The key as a CString.
  • value: The value as a Value.
pub struct MapItem {
    pub key: CString,
    pub value: Value,
}

MapIterator

new

Creates a new MapIterator.

pub(crate) fn new(ptr: *mut mgp_map_items_iterator, memgraph: &Memgraph) -> MapIterator
  • Parameters:
    • ptr: A pointer to mgp_map_items_iterator.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of MapIterator.
next

Returns the next item in the iteration.

fn next(&mut self) -> Option<MapItem>
  • Returns: An Option containing the next MapItem if available, otherwise None.
Drop

Drops the MapIterator and releases the associated resources.

fn drop(&mut self)

MgpValue

new

Creates a new MgpValue.

pub(crate) fn new(ptr: *mut mgp_value, memgraph: &Memgraph) -> MgpValue
  • Parameters:
    • ptr: A pointer to mgp_value.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of MgpValue.
mgp_ptr

Returns the underlying mgp_value pointer.

pub(crate) fn mgp_ptr(&self) -> *mut mgp_value
  • Returns: A pointer to mgp_value.
to_value

Converts the MgpValue to a Value.

pub fn to_value(&self) -> Result<Value>
  • Returns: A Result containing the Value if successful.
make_null

Creates a MgpValue representing a null value.

pub fn make_null(memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_null

Checks if the MgpValue is null.

pub fn is_null(&self) -> bool
  • Returns: true if the MgpValue is null, otherwise false.
make_bool

Creates a MgpValue representing a boolean value.

pub fn make_bool(value: bool, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • value: The boolean value.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_bool

Checks if the MgpValue is a boolean.

pub fn is_bool(&self) -> bool
  • Returns: true if the MgpValue is a boolean, otherwise false.
make_int

Creates a MgpValue representing an integer value.

pub fn make_int(value: i64, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • value: The integer value.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_int

Checks if the MgpValue is an integer.

pub fn is_int(&self) -> bool
  • Returns: true if the MgpValue is an integer, otherwise false.
make_double

Creates a MgpValue representing a double value.

pub fn make_double(value: f64, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • value: The double value.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_double

Checks if the MgpValue is a double.

pub fn is_double(&self) -> bool
  • Returns: true if the MgpValue is a double, otherwise false.
make_string

Creates a MgpValue representing a string value.

pub fn make_string(value: &CStr, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • value: The string value as a CStr.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_string

Checks if the MgpValue is a string.

pub fn is_string(&self) -> bool
  • Returns: true if the MgpValue is a string, otherwise false.
make_list

Creates a MgpValue representing a list value.

pub fn make_list(list: &List, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • list: The List to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_list

Checks if the MgpValue is a list.

pub fn is_list(&self) -> bool
  • Returns: true if the MgpValue is a list, otherwise false.
make_map

Creates a MgpValue representing a map value.

pub fn make_map(map: &Map, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • map: The Map to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_map

Checks if the MgpValue is a map.

pub fn is_map(&self) -> bool
  • Returns: true if the MgpValue is a map, otherwise false.
make_vertex

Creates a MgpValue representing a vertex value.

pub fn make_vertex(vertex: &Vertex, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • vertex: The Vertex to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_vertex

Checks if the MgpValue is a vertex.

pub fn is_vertex(&self) -> bool
  • Returns: true if the MgpValue is a vertex, otherwise false.
make_edge

Creates a MgpValue representing an edge value.

pub fn make_edge(edge: &Edge, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • edge: The Edge to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_edge

Checks if the MgpValue is an edge.

pub fn is_edge(&self) -> bool
  • Returns: true if the MgpValue is an edge, otherwise false.
make_path

Creates a MgpValue representing a path value.

pub fn make_path(path: &Path, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • path: The Path to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_path

Checks if the MgpValue is a path.

pub fn is_path(&self) -> bool
  • Returns: true if the MgpValue is a path, otherwise false.
make_date

Creates a MgpValue representing a date value.

pub fn make_date(date: &NaiveDate, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • date: The NaiveDate to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_date

Checks if the MgpValue is a date.

pub fn is_date(&self) -> bool
  • Returns: true if the MgpValue is a date, otherwise false.
make_local_time

Creates a MgpValue representing a local time value.

pub fn make_local_time(time: &NaiveTime, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • time: The NaiveTime to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_local_time

Checks if the MgpValue is a local time.

pub fn is_local_time(&self) -> bool
  • Returns: true if the MgpValue is a local time, otherwise false.
make_local_date_time

Creates a MgpValue representing a local date-time value.

pub fn make_local_date_time(datetime: &NaiveDateTime
 
, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • datetime: The NaiveDateTime to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_local_date_time

Checks if the MgpValue is a local date-time.

pub fn is_local_date_time(&self) -> bool
  • Returns: true if the MgpValue is a local date-time, otherwise false.
make_duration

Creates a MgpValue representing a duration value.

pub fn make_duration(duration: &chrono::Duration, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • duration: The Duration to be converted.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new MgpValue if successful.
is_duration

Checks if the MgpValue is a duration.

pub fn is_duration(&self) -> bool
  • Returns: true if the MgpValue is a duration, otherwise false.
Drop

Drops the MgpValue and releases the associated resources.

fn drop(&mut self)

Path

new

Creates a new Path.

pub(crate) fn new(ptr: *mut mgp_path, memgraph: &Memgraph) -> Path
  • Parameters:
    • ptr: A pointer to mgp_path.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of Path.
mgp_copy

Creates a copy of an existing Path.

pub(crate) unsafe fn mgp_copy(mgp_path: *mut mgp_path, memgraph: &Memgraph) -> Result<Path>
  • Parameters:
    • mgp_path: A pointer to mgp_path.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a copied Path if successful.
mgp_ptr

Returns the underlying mgp_path pointer.

pub(crate) fn mgp_ptr(&self) -> *mut mgp_path
  • Returns: A pointer to mgp_path.
set_mgp_ptr

Sets a new mgp_path pointer.

pub(crate) fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_path)
  • Parameters:
    • new_ptr: A new pointer to mgp_path.
size

Returns the size of the Path.

pub fn size(&self) -> u64
  • Returns: The size of the Path.
make_with_start

Creates a new Path starting with the specified Vertex.

pub fn make_with_start(vertex: &Vertex, memgraph: &Memgraph) -> Result<Path>
  • Parameters:
    • vertex: The starting Vertex.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new Path if successful.
expand

Expands the Path by adding an Edge. Fails if the current last vertex in the path is not part of the given edge or if there is no memory to expand the path.

pub fn expand(&self, edge: &Edge) -> Result<()>
  • Parameters:
    • edge: The Edge to add.
  • Returns: A Result indicating success or failure.
vertex_at

Returns the Vertex at the specified index.

pub fn vertex_at(&self, index: u64) -> Result<Vertex>
  • Parameters:
    • index: The index of the Vertex to retrieve.
  • Returns: A Result containing the Vertex if successful.
edge_at

Returns the Edge at the specified index.

pub fn edge_at(&self, index: u64) -> Result<Edge>
  • Parameters:
    • index: The index of the Edge to retrieve.
  • Returns: A Result containing the Edge if successful.
Drop

Drops the Path and releases the associated resources.

fn drop(&mut self)

Property

Represents a property with a name and value.

pub struct Property {
    pub name: CString,
    pub value: Value,
}
  • Fields:
    • name: The name of the property as a CString.
    • value: The value of the property as a Value.

PropertiesIterator

new

Creates a new PropertiesIterator.

pub(crate) fn new(ptr: *mut mgp_properties_iterator, memgraph: &Memgraph) -> PropertiesIterator
  • Parameters:
    • ptr: A pointer to mgp_properties_iterator.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A new instance of PropertiesIterator.
next

Returns the next property in the iteration.

fn next(&mut self) -> Option<Property>
  • Returns: An Option containing the next Property if available, otherwise None.
Drop

Drops the PropertiesIterator and releases the associated resources.

fn drop(&mut self)

ResultRecord

create

Creates a new ResultRecord.

pub fn create(memgraph: &Memgraph) -> Result<ResultRecord>
  • Parameters:
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new ResultRecord if successful.
insert_mgp_value

Inserts an MgpValue into the ResultRecord.

pub fn insert_mgp_value(&self, field: &CStr, value: &MgpValue) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The MgpValue to insert.
  • Returns: A Result indicating success or failure.
insert_null

Inserts a null value into the ResultRecord.

pub fn insert_null(&self, field: &CStr) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
  • Returns: A Result indicating success or failure.
insert_bool

Inserts a boolean value into the ResultRecord.

pub fn insert_bool(&self, field: &CStr, value: bool) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The boolean value to insert.
  • Returns: A Result indicating success or failure.
insert_int

Inserts an integer value into the ResultRecord.

pub fn insert_int(&self, field: &CStr, value: i64) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The integer value to insert.
  • Returns: A Result indicating success or failure.
insert_double

Inserts a double value into the ResultRecord.

pub fn insert_double(&self, field: &CStr, value: f64) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The double value to insert.
  • Returns: A Result indicating success or failure.
insert_string

Inserts a string value into the ResultRecord.

pub fn insert_string(&self, field: &CStr, value: &CStr) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The string value as a CStr to insert.
  • Returns: A Result indicating success or failure.
insert_list

Inserts a list value into the ResultRecord.

pub fn insert_list(&self, field: &CStr, value: &List) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The List to insert.
  • Returns: A Result indicating success or failure.
insert_map

Inserts a map value into the ResultRecord.

pub fn insert_map(&self, field: &CStr, value: &Map) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The Map to insert.
  • Returns: A Result indicating success or failure.
insert_vertex

Inserts a vertex value into the ResultRecord.

pub fn insert_vertex(&self, field: &CStr, value: &Vertex) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The Vertex to insert.
  • Returns: A Result indicating success or failure.
insert_edge

Inserts an edge value into the ResultRecord.

pub fn insert_edge(&self, field: &CStr, value: &Edge) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The Edge to insert.
  • Returns: A Result indicating success or failure.
insert_path

Inserts a path value into the ResultRecord.

pub fn insert_path(&self, field: &CStr, value: &Path) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The Path to insert.
  • Returns: A Result indicating success or failure.
insert_date

Inserts a date value into the ResultRecord.

pub fn insert_date(&self, field: &CStr, value: &NaiveDate) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The NaiveDate to insert.
  • Returns: A Result indicating success or failure.
insert_local_time

Inserts a local time value into the ResultRecord.

pub fn insert_local_time(&self, field: &CStr, value: &NaiveTime) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The NaiveTime to insert.
  • Returns: A Result indicating success or failure.
insert_local_date_time

Inserts a local date-time value into the ResultRecord.

pub fn insert_local_date_time(&self, field: &CStr, value: &NaiveDateTime) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The NaiveDateTime to insert.
  • Returns: A Result indicating success or failure.
insert_duration

Inserts a duration value into the ResultRecord.

pub fn insert_duration(&self, field: &CStr, value: &chrono::Duration) -> Result<()>
  • Parameters:
    • field: The field name as a CStr.
    • value: The Duration to insert.
  • Returns: A Result indicating success or failure.

Error

Defines various errors that can occur in the API.

#[derive(Debug, PartialEq, Snafu)]
#[snafu(visibility = "pub")]
pub enum Error {
    UnableToCreateDateFromNaiveDate,
    UnableToCreateDurationFromChronoDuration,
    UnableToCopyEdge,
    UnableToReturnEdgePropertyValueAllocationError,
    UnableToReturnEdgePropertyValueCreationError,
    UnableToReturnEdgePropertyNameAllocationError,
    UnableToReturnEdgePropertyDeletedObjectError,
    UnableToReturnEdgePropertiesIterator,
    UnableToCreateEmptyList,
    UnableToCopyList,
    UnableToAppendListValue,
    UnableToAppendExtendListValue,
    UnableToAccessListValueByIndex,
    UnableToCreateLocalTimeFromNaiveTime,
    UnableToCreateLocalDateTimeFromNaiveDateTime,
    UnableToCopyMap,
    UnableToCreateEmptyMap,
    UnableToInsertMapValue,
    UnableToAccessMapValue,
    UnableToCreateMapIterator,
    UnableToCreateGraphVerticesIterator,
    UnableToFindVertexById,
    UnableToRegisterReadProcedure,
    UnableToAddRequiredArguments,
    UnableToAddOptionalArguments,
    UnableToAddReturnType,
    UnableToAddDeprecatedReturnType,
    UnableToCopyPath,
    OutOfBoundPathVertexIndex,
    OutOfBoundPathEdgeIndex,
    UnableToCreatePathWithStartVertex,
    UnableToExpandPath,
    UnableToCreateResultRecord,
    UnableToInsertResultValue,
    UnableToCreateCString,
    UnableToMakeNullValue,
    UnableToMakeBoolValue,
    UnableToMakeIntegerValue,
    UnableToMakeDoubleValue,
    UnableToMakeMemgraphStringValue,
    UnableToMakeListValue,
    UnableToMakeMapValue,
    UnableToMakeVertexValue,
    UnableToMakeEdgeValue,
    UnableToMakePathValue,
    UnableToMakeValueString,
    UnableToMakeDateValue,
    UnableToMakeLocalTimeValue,
    UnableToMakeLocalDateTimeValue,
    UnableToMakeDurationValue,
    UnableToCopyVertex,
    OutOfBoundLabelIndexError,
    UnableToGetVertexProperty,
    UnableToReturnVertexPropertyMakeNameEror,
    UnableToReturnVertexPropertiesIterator,
    UnableToReturnVertexInEdgesIterator,
    UnableToReturnVertexOutEdgesIterator,
    UnableToReturnVertexLabelsCountDeletedObjectError,
    UnableToReturnVertexLabelDeletedObjectError,
    UnableToCheckVertexHasLabel,
}

Result

Defines a result type holding Error by default.

pub type Result<T, E = Error> = std::result::Result<T, E>;
  • T: The type of the success value.
  • E: The type of the error value (default is Error).

Date

new

Creates a new Date.

pub(crate) fn new(ptr: *mut mgp_date) -> Date
  • Parameters:
    • ptr: A pointer to mgp_date.
  • Returns: A new instance of Date.
from_naive_date

Creates a Date from a NaiveDate.

pub fn from_naive_date(from: &NaiveDate, memgraph: &Memgraph) -> Result<Date>
  • Parameters:
    • from: A reference to a NaiveDate.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new Date if successful.
to_naive_date

Converts the Date to a NaiveDate.

pub fn to_naive_date(&self) -> NaiveDate
  • Returns: A NaiveDate representing the Date.
mgp_ptr

Returns the underlying mgp_date pointer.

pub fn mgp_ptr(&self) -> *mut mgp_date
  • Returns: A pointer to mgp_date.
set_mgp_ptr

Sets a new mgp_date pointer.

pub fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_date)
  • Parameters:
    • new_ptr: A new pointer to mgp_date.
year

Returns the year of the Date.

pub fn year(&self) -> i32
  • Returns: The year of the Date.
month

Returns the month of the Date.

pub fn month(&self) -> u32
  • Returns: The month of the Date.
day

Returns the day of the Date.

pub fn day(&self) -> u32
  • Returns: The day of the Date.
Drop

Drops the Date and releases the associated resources.

fn drop(&mut self)

LocalTime

new

Creates a new LocalTime.

pub(crate) fn new(ptr: *mut mgp_local_time) -> LocalTime
  • Parameters:
    • ptr: A pointer to mgp_local_time.
  • Returns: A new instance of LocalTime.
from_naive_time

Creates a LocalTime from a NaiveTime.

pub fn from_naive_time(from: &NaiveTime, memgraph: &Memgraph) -> Result<LocalTime>
  • Parameters:
    • from: A reference to a NaiveTime.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new LocalTime if successful.
to_naive_time

Converts the LocalTime to a NaiveTime.

pub fn to_naive_time(&self) -> NaiveTime
  • Returns: A NaiveTime representing the LocalTime.
mgp_ptr

Returns the underlying mgp_local_time pointer.

pub fn mgp_ptr(&self) -> *mut mgp_local_time
  • Returns: A pointer to mgp_local_time.
set_mgp_ptr

Sets a new mgp_local_time pointer.

pub fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_local_time)
  • Parameters:
    • new_ptr: A new pointer to mgp_local_time.
hour

Returns the hour of the LocalTime.

pub fn hour(&self) -> u32
  • Returns: The hour of the LocalTime.
minute

Returns the minute of the LocalTime.

pub fn minute(&self) -> u32
  • Returns: The minute of the LocalTime.
second

Returns the second of the LocalTime.

pub fn second(&self) -> u32
  • Returns: The second of the LocalTime.
millisecond

Returns the millisecond of the LocalTime.

pub fn millisecond(&self) -> u32
  • Returns: The millisecond of the LocalTime.
microsecond

Returns the microsecond of the LocalTime.

pub fn microsecond(&self) -> u32
  • Returns: The microsecond of the LocalTime.
timestamp

Returns the timestamp of the LocalTime.

pub fn timestamp(&self) -> i64
  • Returns: The timestamp of the LocalTime.
Drop

Drops the LocalTime and releases the associated resources.

fn drop(&mut self)

LocalDateTime

new

Creates a new LocalDateTime.

pub(crate) fn new(ptr: *mut mgp_local_date_time) -> LocalDateTime
  • Parameters:
    • ptr: A pointer to mgp_local_date_time.
  • Returns: A new instance of LocalDateTime.
from_naive_date_time

Creates a LocalDateTime from a NaiveDateTime.

pub fn from_naive_date_time(from: &NaiveDateTime, memgraph: &Memgraph) -> Result<LocalDateTime>
  • Parameters:
    • from: A reference to a NaiveDateTime.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new LocalDateTime if successful.
to_naive_date_time

Converts the LocalDateTime to a NaiveDateTime.

pub fn to_naive_date_time(&self) -> NaiveDateTime
  • Returns: A NaiveDateTime representing the LocalDateTime.
mgp_ptr

Returns the underlying mgp_local_date_time pointer.

pub fn mgp_ptr(&self) -> *mut mgp_local_date_time
  • Returns: A pointer to mgp_local_date_time.
set_mgp_ptr

Sets a new mgp_local_date_time pointer.

pub fn set_mgp_ptr(&mut self, new_ptr: *mut mgp_local_date_time)
  • Parameters:
    • new_ptr: A new pointer to mgp_local_date_time.
year

Returns the year of the LocalDateTime.

pub fn year(&self) -> i32
  • Returns: The year of the LocalDateTime.
month

Returns the month of the LocalDateTime.

pub fn month(&self) -> u32
  • Returns: The month of the LocalDateTime.
day

Returns the day of the LocalDateTime.

pub fn day(&self) -> u32
  • Returns: The day of the LocalDateTime.
hour

Returns the hour of the LocalDateTime.

pub fn hour(&self) -> u32
  • Returns: The hour of the LocalDateTime.
minute

Returns the minute of the LocalDateTime.

pub fn minute(&self) -> u32
  • Returns: The minute of the LocalDateTime.
second

Returns the second of the LocalDateTime.

pub fn second(&self) -> u32
  • Returns: The second of the LocalDateTime.
millisecond

Returns the millisecond of the LocalDateTime.

pub fn millisecond(&self) -> u32
  • Returns: The millisecond of the LocalDateTime.
microsecond

Returns the microsecond of the LocalDateTime.

pub fn microsecond(&self) -> u32
  • Returns: The microsecond of the LocalDateTime.
Drop

Drops the LocalDateTime and releases the associated resources.

fn drop(&mut self)

Duration

new

Creates a new Duration.

pub(crate) fn new(ptr: *mut mgp_duration) -> Duration
  • Parameters:
    • ptr: A pointer to mgp_duration.
  • Returns: A new instance of Duration.
from_chrono_duration

Creates a Duration from a chrono::Duration.

pub fn from_chrono_duration(from: &chrono::Duration, memgraph: &Memgraph) -> Result<Duration>
  • Parameters:
    • from: A reference to a chrono::Duration.
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing a new Duration if successful.
to_chrono_duration

Converts the Duration to a chrono::Duration.

pub fn to_chrono_duration(&self) -> chrono::Duration

Value

to_mgp_value

Converts a Value to a MgpValue.

pub fn to_mgp_value(&self, memgraph: &Memgraph) -> Result<MgpValue>
  • Parameters:
    • memgraph: A reference to a Memgraph instance.
  • Returns: A Result containing the MgpValue if successful.

create_cstring

Creates a copy of the provided string.

pub(crate) unsafe fn create_cstring(c_char_ptr: *const c_char) -> Result<CString>
  • Parameters:
    • c_char_ptr: A pointer to a C string.
  • Returns: A Result containing a CString if successful.

mgp_raw_value_to_value

Creates a Value object from a mgp_value object.

pub(crate) unsafe fn mgp_raw_value_to_value(value: *mut mgp_value, memgraph: &Memgraph) -> Result<Value>

  • Parameters:

    • value: A pointer to mgp_value.
    • memgraph: A reference to a Memgraph instance.

  • Returns: A Result containing the Value if successful.

  • Safety: Calls C API unsafe functions. The provided mgp_value object has to be a valid non-null pointer.

Enums

Value

Represents different types of values.

pub enum Value {
    Null,
    Bool(bool),
    Int(i64),
    Float(f64),
    String(CString),
    Vertex(Vertex),
    Edge(Edge),
    Path(Path),
    List(List),
    Map(Map),
    Date(NaiveDate),
    LocalTime(NaiveTime),
    LocalDateTime(NaiveDateTime),
    Duration(chrono::Duration),
}
  • Variants:
    • Null: Represents a null value.
    • Bool(bool): Represents a boolean value.
    • Int(i64): Represents an integer value.
    • Float(f64): Represents a floating-point value.
    • String(CString): Represents a string value.
    • Vertex(Vertex): Represents a vertex value.
    • Edge(Edge): Represents an edge value.
    • Path(Path): Represents a path value.
    • List(List): Represents a list value.
    • Map(Map): Represents a map value.
    • Date(NaiveDate): Represents a date value.
    • LocalTime(NaiveTime): Represents a local time value.
    • LocalDateTime(NaiveDateTime): Represents a local date-time value.
    • Duration(chrono::Duration): Represents a duration value.