LiteGraph is a lightweight graph database with both relational and vector support, built using Sqlite, with support for exporting to GEXF. LiteGraph is intended to be a multi-modal database primarily for providing persistence and retrieval for knowledge and artificial intelligence applications.
LiteGraph can be run in-process (using LiteGraphClient) or as a standalone RESTful server (using LiteGraph.Server).
- Added support for labels on graphs, nodes, edges (string list)
- Added support for vector persistence and search
- Updated SDK, test, and Postman collections accordingly
- Updated GEXF export to support labels and tags
- Internal refactor to reduce code bloat
- Multiple bugfixes and QoL improvements
Please feel free to start an issue or a discussion!
Embedding LiteGraph into your application is simple and requires no configuration of users or credentials. Refer to the Test project for a full example.
using LiteGraph;
LiteGraphClient graph = new LiteGraphClient(); // using Sqlite file litegraph.db
LiteGraphClient graph = new LiteGraphClient(
new SqliteRepository("mydatabase.db")
); // use a specific file
graph.InitializeRepository();
// Create a tenant
TenantMetadata tenant = graph.CreateTenant(Guid.NewGuid(), "My tenant");
// Create a graph
Graph graph = graph.CreateGraph(tenant.GUID, "This is my graph!");
// Create nodes
Node node1 = graph.CreateNode(tenant.GUID, graph.GUID, new Node { Name = "node1" });
Node node2 = graph.CreateNode(tenant.GUID, graph.GUID, new Node { Name = "node2" });
Node node3 = graph.CreateNode(tenant.GUID, graph.GUID, new Node { Name = "node3" });
// Create edges
Edge edge1 = graph.CreateEdge(tenant.GUID, graph.GUID, node1.GUID, node2.GUID, "Node 1 to node 2");
Edge edge2 = graph.CreateEdge(tenant.GUID, graph.GUID, node2.GUID, node3.GUID, "Node 2 to node 3");
// Find routes
foreach (RouteDetail route in graph.GetRoutes(
SearchTypeEnum.DepthFirstSearch,
tenant.GUID,
graph.GUID,
node1.GUID,
node2.GUID))
{
Console.WriteLine(...);
}
// Export to GEXF file
graph.ExportGraphToGexfFile(tenant.GUID, graph.GUID, "mygraph.gexf");The Labels property is a List<string> allowing to attach labels to any Graph, Node, or Edge. The Tags property is a NameValueCollection allowing you to attach key-value pairs to any Graph, Node, or Edge. These objects are stored in separate look-aside tables which are consulted or modified upon creation, update, deletion, retrieval, or search of the aforementioned types.
The Data property can also be attached to any Graph, Node, or Edge object and supports any object serializable to JSON. This value is retrieved when reading or searching objects, and filters can be created to retrieve only objects that have matches based on elements in the object stored in Data. Refer to ExpressionTree for information on how to craft expressions.
All of these properties can be used in conjunction with one another.
List<string> labels = new List<string>
{
"test",
"label1"
};
graph.CreateNode(tenant.GUID, new Node { Name = "Joel", Labels = labels });
foreach (Node node in graph.ReadNodes(tenant.GUID, graph.GUID, labels))
{
Console.WriteLine(...);
}NameValueCollection nvc = new NameValueCollection();
nvc.Add("key", "value");
graph.CreateNode(tenant.GUID, new Node { Name = "Joel", Tags = nvc });
foreach (Node node in graph.ReadNodes(tenant.GUID, graph.GUID, null, nvc))
{
Console.WriteLine(...);
}using ExpressionTree;
class Person
{
public string Name { get; set; } = null;
public int Age { get; set; } = 0;
public string City { get; set; } = "San Jose";
}
Person person1 = new Person { Name = "Joel", Age = 47, City = "San Jose" };
graph.CreateNode(tenant.GUID, graph.GUID, new Node { Name = "Joel", Data = person1 });
Expr expr = new Expr
{
"Left": "City",
"Operator": "Equals",
"Right": "San Jose"
};
foreach (Node node in graph.ReadNodes(tenant.GUID, graph.GUID, null, expr))
{
Console.WriteLine(...);
}It is important to note that vectors have a dimensionality (number of array elements) and vector searches are only performed against graphs, nodes, and edges where the attached vector objects have a dimensionality consistent with the input.
Further, it is strongly recommended that you make extensive use of labels, tags, and expressions (data filters) when performing a vector search to reduce the number of calculations to compute score, distance, and inner product.
using ExpressionTree;
class Person
{
public string Name { get; set; } = null;
public int Age { get; set; } = 0;
public string City { get; set; } = "San Jose";
}
Person person1 = new Person { Name = "Joel", Age = 47, City = "San Jose" };
VectorMetadata vectors = new VectorMetadata
{
Model = "testmodel",
Dimensionality = 3,
Content = "testcontent",
Vectors = new List<float> { 0.1f, 0.2f, 0.3f }
};
graph.CreateNode(new Node { Name = "Joel", Data = person1 }, Vectors = new List<VectorMetadata> { vectors });
foreach (VectorSearchResult result in graph.SearchVectors(
VectorSearchDomainEnum.Node,
VectorSearchTypeEnum.CosineSimilarity,
new List<float> { 0.1f, 0.2f, 0.3f },
tenant.GUID,
graph.GUID,
null, // labels
null, // tags
null, // filter
))
{
Console.WriteLine("Node " + result.Node.GUID + " score " + result.Score);
}LiteGraph includes a project called LiteGraph.Server which allows you to deploy a RESTful front-end for LiteGraph. Refer to REST_API.md and also the Postman collection in the root of this repository for details. By default, LiteGraph.Server listens on http://localhost:8701 and is only accessible to localhost. Modify the litegraph.json file to change settings including hostname and port.
Listening on a specific hostname should not require elevated privileges. However, listening on any hostname (i.e. using * or 0.0.0.0 will require elevated privileges).
$ cd LiteGraph.Server/bin/Debug/net8.0
$ dotnet LiteGraph.Server.dll
_ _ _ _
| (_) |_ ___ __ _ _ _ __ _ _ __| |_
| | | _/ -_) _` | '_/ _` | '_ \ ' \
|_|_|\__\___\__, |_| \__,_| .__/_||_|
|___/ |_|
LiteGraph Server
(c)2025 Joel Christner
Using settings file './litegraph.json'
Settings file './litegraph.json' does not exist, creating
Initializing logging
| syslog://127.0.0.1:514
2025-01-27 22:09:08 joel-laptop Debug [LiteGraphServer] logging initialized
Creating default records in database litegraph.db
| Created tenant : 00000000-0000-0000-0000-000000000000
| Created user : 00000000-0000-0000-0000-000000000000 email: default@user.com pass: password
| Created credential : 00000000-0000-0000-0000-000000000000 bearer token: default
| Created graph : 00000000-0000-0000-0000-000000000000 Default graph
Finished creating default records
2025-01-27 22:09:09 joel-laptop Debug [ServiceHandler] initialized service handler
2025-01-27 22:09:09 joel-laptop Info [RestServiceHandler] starting REST server on http://localhost:8701/
2025-01-27 22:09:09 joel-laptop Alert [RestServiceHandler]
NOTICE
------
LiteGraph is configured to listen on localhost and will not be externally accessible.
Modify ./litegraph.json to change the REST listener hostname to make externally accessible.
2025-01-27 22:09:09 joel-laptop Info [LiteGraphServer] started at 01/27/2025 10:09:09 PM using process ID 56556A Docker image is available in Docker Hub under jchristn/litegraph. Use the Docker Compose start (compose-up.sh and compose-up.bat) and stop (compose-down.sh and compose-down.bat) scripts in the Docker directory if you wish to run within Docker Compose. Ensure that you have a valid database file (e.g. litegraph.db) and configuration file (e.g. litegraph.json) exposed into your container.
Please refer to CHANGELOG.md for version history.