Implement the missing methods.

lightrag/kg/age_impl.py

@@ -8,7 +8,7 @@ from dataclasses import dataclass
 from typing import Any, Dict, List, NamedTuple, Optional, Union, final
 import numpy as np
 import pipmaster as pm
-from lightrag.types import KnowledgeGraph
+from lightrag.types import KnowledgeGraph, KnowledgeGraphNode, KnowledgeGraphEdge
 
 from tenacity import (
     retry,
@@ -613,20 +613,258 @@ class AGEStorage(BaseGraphStorage):
             await self._driver.putconn(connection)
 
     async def delete_node(self, node_id: str) -> None:
-        raise NotImplementedError
+        """Delete a node with the specified label
+
+        Args:
+            node_id: The label of the node to delete
+        """
+        entity_name_label = node_id.strip('"')
+        
+        query = """
+        MATCH (n:`{label}`)
+        DETACH DELETE n
+        """
+        params = {"label": AGEStorage._encode_graph_label(entity_name_label)}
+        try:
+            await self._query(query, **params)
+            logger.debug(f"Deleted node with label '{entity_name_label}'")
+        except Exception as e:
+            logger.error(f"Error during node deletion: {str(e)}")
+            raise
+
+    async def remove_nodes(self, nodes: list[str]):
+        """Delete multiple nodes
+
+        Args:
+            nodes: List of node labels to be deleted
+        """
+        for node in nodes:
+            await self.delete_node(node)
+
+    async def remove_edges(self, edges: list[tuple[str, str]]):
+        """Delete multiple edges
+
+        Args:
+            edges: List of edges to be deleted, each edge is a (source, target) tuple
+        """
+        for source, target in edges:
+            entity_name_label_source = source.strip('"')
+            entity_name_label_target = target.strip('"')
+            
+            query = """
+            MATCH (source:`{src_label}`)-[r]->(target:`{tgt_label}`)
+            DELETE r
+            """
+            params = {
+                "src_label": AGEStorage._encode_graph_label(entity_name_label_source),
+                "tgt_label": AGEStorage._encode_graph_label(entity_name_label_target)
+            }
+            try:
+                await self._query(query, **params)
+                logger.debug(f"Deleted edge from '{entity_name_label_source}' to '{entity_name_label_target}'")
+            except Exception as e:
+                logger.error(f"Error during edge deletion: {str(e)}")
+                raise
 
     async def embed_nodes(
         self, algorithm: str
     ) -> tuple[np.ndarray[Any, Any], list[str]]:
-        raise NotImplementedError
+        """Embed nodes using the specified algorithm
+
+        Args:
+            algorithm: Name of the embedding algorithm
+
+        Returns:
+            tuple: (embedding matrix, list of node identifiers)
+        """
+        if algorithm not in self._node_embed_algorithms:
+            raise ValueError(f"Node embedding algorithm {algorithm} not supported")
+        return await self._node_embed_algorithms[algorithm]()
 
     async def get_all_labels(self) -> list[str]:
-        raise NotImplementedError
+        """Get all node labels in the database
+        
+        Returns:
+            ["label1", "label2", ...]  # Alphabetically sorted label list
+        """
+        query = """
+        MATCH (n)
+        RETURN DISTINCT labels(n) AS node_labels
+        """
+        results = await self._query(query)
+        
+        all_labels = []
+        for record in results:
+            if record and "node_labels" in record:
+                for label in record["node_labels"]:
+                    if label:
+                        # Decode label
+                        decoded_label = AGEStorage._decode_graph_label(label)
+                        all_labels.append(decoded_label)
+        
+        # Remove duplicates and sort
+        return sorted(list(set(all_labels)))
 
     async def get_knowledge_graph(
         self, node_label: str, max_depth: int = 5
     ) -> KnowledgeGraph:
-        raise NotImplementedError
+        """
+        Retrieve a connected subgraph of nodes where the label includes the specified 'node_label'.
+        Maximum number of nodes is constrained by the environment variable 'MAX_GRAPH_NODES' (default: 1000).
+        When reducing the number of nodes, the prioritization criteria are as follows:
+            1. Label matching nodes take precedence (nodes containing the specified label string)
+            2. Followed by nodes directly connected to the matching nodes
+            3. Finally, the degree of the nodes
+
+        Args:
+            node_label: String to match in node labels (will match any node containing this string in its label)
+            max_depth: Maximum depth of the graph. Defaults to 5.
+            
+        Returns:
+            KnowledgeGraph: Complete connected subgraph for specified node
+        """
+        max_graph_nodes = int(os.getenv("MAX_GRAPH_NODES", 1000))
+        result = KnowledgeGraph()
+        seen_nodes = set()
+        seen_edges = set()
+        
+        # Handle special case for "*" label
+        if node_label == "*":
+            # Query all nodes and sort by degree
+            query = """
+            MATCH (n)
+            OPTIONAL MATCH (n)-[r]-()
+            WITH n, count(r) AS degree
+            ORDER BY degree DESC
+            LIMIT {max_nodes}
+            RETURN n, degree
+            """
+            params = {"max_nodes": max_graph_nodes}
+            nodes_result = await self._query(query, **params)
+            
+            # Add nodes to result
+            node_ids = []
+            for record in nodes_result:
+                if "n" in record:
+                    node = record["n"]
+                    node_id = str(node.get("id", ""))
+                    if node_id not in seen_nodes:
+                        node_properties = {k: v for k, v in node.items()}
+                        node_label = node.get("label", "")
+                        result.nodes.append(
+                            KnowledgeGraphNode(
+                                id=node_id,
+                                labels=[node_label],
+                                properties=node_properties
+                            )
+                        )
+                        seen_nodes.add(node_id)
+                        node_ids.append(node_id)
+            
+            # Query edges between these nodes
+            if node_ids:
+                edges_query = """
+                MATCH (a)-[r]->(b)
+                WHERE a.id IN {node_ids} AND b.id IN {node_ids}
+                RETURN a, r, b
+                """
+                edges_params = {"node_ids": node_ids}
+                edges_result = await self._query(edges_query, **edges_params)
+                
+                # Add edges to result
+                for record in edges_result:
+                    if "r" in record and "a" in record and "b" in record:
+                        source = record["a"].get("id", "")
+                        target = record["b"].get("id", "")
+                        edge_id = f"{source}-{target}"
+                        if edge_id not in seen_edges:
+                            edge_properties = {k: v for k, v in record["r"].items()}
+                            result.edges.append(
+                                KnowledgeGraphEdge(
+                                    id=edge_id,
+                                    type="DIRECTED",
+                                    source=source,
+                                    target=target,
+                                    properties=edge_properties
+                                )
+                            )
+                            seen_edges.add(edge_id)
+        else:
+            # For specific label, use partial matching
+            entity_name_label = node_label.strip('"')
+            encoded_label = AGEStorage._encode_graph_label(entity_name_label)
+            
+            # Find matching start nodes
+            start_query = """
+            MATCH (n:`{label}`)
+            RETURN n
+            """
+            start_params = {"label": encoded_label}
+            start_nodes = await self._query(start_query, **start_params)
+            
+            if not start_nodes:
+                logger.warning(f"No nodes found with label '{entity_name_label}'!")
+                return result
+            
+            # Traverse graph from each start node
+            for start_node_record in start_nodes:
+                if "n" in start_node_record:
+                    start_node = start_node_record["n"]
+                    start_id = str(start_node.get("id", ""))
+                    
+                    # Use BFS to traverse graph
+                    query = """
+                    MATCH (start:`{label}`)
+                    CALL {
+                        MATCH path = (start)-[*0..{max_depth}]->(n)
+                        RETURN nodes(path) AS path_nodes, relationships(path) AS path_rels
+                    }
+                    RETURN DISTINCT path_nodes, path_rels
+                    """
+                    params = {"label": encoded_label, "max_depth": max_depth}
+                    results = await self._query(query, **params)
+                    
+                    # Extract nodes and edges from results
+                    for record in results:
+                        if "path_nodes" in record:
+                            # Process nodes
+                            for node in record["path_nodes"]:
+                                node_id = str(node.get("id", ""))
+                                if node_id not in seen_nodes and len(seen_nodes) < max_graph_nodes:
+                                    node_properties = {k: v for k, v in node.items()}
+                                    node_label = node.get("label", "")
+                                    result.nodes.append(
+                                        KnowledgeGraphNode(
+                                            id=node_id,
+                                            labels=[node_label],
+                                            properties=node_properties
+                                        )
+                                    )
+                                    seen_nodes.add(node_id)
+                        
+                        if "path_rels" in record:
+                            # Process edges
+                            for rel in record["path_rels"]:
+                                source = str(rel.get("start_id", ""))
+                                target = str(rel.get("end_id", ""))
+                                edge_id = f"{source}-{target}"
+                                if edge_id not in seen_edges:
+                                    edge_properties = {k: v for k, v in rel.items()}
+                                    result.edges.append(
+                                        KnowledgeGraphEdge(
+                                            id=edge_id,
+                                            type=rel.get("label", "DIRECTED"),
+                                            source=source,
+                                            target=target,
+                                            properties=edge_properties
+                                        )
+                                    )
+                                    seen_edges.add(edge_id)
+        
+        logger.info(
+            f"Subgraph query successful | Node count: {len(result.nodes)} | Edge count: {len(result.edges)}"
+        )
+        return result
 
     async def index_done_callback(self) -> None:
         # AGES handles persistence automatically

lightrag/kg/chroma_impl.py

@@ -193,7 +193,37 @@ class ChromaVectorDBStorage(BaseVectorStorage):
         pass
 
     async def delete_entity(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete an entity by its ID.
+        
+        Args:
+            entity_name: The ID of the entity to delete
+        """
+        try:
+            logger.info(f"Deleting entity with ID {entity_name} from {self.namespace}")
+            self._collection.delete(ids=[entity_name])
+        except Exception as e:
+            logger.error(f"Error during entity deletion: {str(e)}")
+            raise
 
     async def delete_entity_relation(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete an entity and its relations by ID. 
+        In vector DB context, this is equivalent to delete_entity.
+        
+        Args:
+            entity_name: The ID of the entity to delete
+        """
+        await self.delete_entity(entity_name)
+        
+    async def delete(self, ids: list[str]) -> None:
+        """Delete vectors with specified IDs
+        
+        Args:
+            ids: List of vector IDs to be deleted
+        """
+        try:
+            logger.info(f"Deleting {len(ids)} vectors from {self.namespace}")
+            self._collection.delete(ids=ids)
+            logger.debug(f"Successfully deleted {len(ids)} vectors from {self.namespace}")
+        except Exception as e:
+            logger.error(f"Error while deleting vectors from {self.namespace}: {e}")
+            raise

lightrag/kg/gremlin_impl.py

@@ -16,7 +16,7 @@ from tenacity import (
     wait_exponential,
 )
 
-from lightrag.types import KnowledgeGraph
+from lightrag.types import KnowledgeGraph, KnowledgeGraphNode, KnowledgeGraphEdge
 from lightrag.utils import logger
 
 from ..base import BaseGraphStorage
@@ -396,17 +396,286 @@ class GremlinStorage(BaseGraphStorage):
         print("Implemented but never called.")
 
     async def delete_node(self, node_id: str) -> None:
-        raise NotImplementedError
+        """Delete a node with the specified entity_name
+        
+        Args:
+            node_id: The entity_name of the node to delete
+        """
+        entity_name = GremlinStorage._fix_name(node_id)
+        
+        query = f"""g
+                 .V().has('graph', {self.graph_name})
+                 .has('entity_name', {entity_name})
+                 .drop()
+                 """
+        try:
+            await self._query(query)
+            logger.debug(
+                "{%s}: Deleted node with entity_name '%s'",
+                inspect.currentframe().f_code.co_name,
+                entity_name
+            )
+        except Exception as e:
+            logger.error(f"Error during node deletion: {str(e)}")
+            raise
 
     async def embed_nodes(
         self, algorithm: str
     ) -> tuple[np.ndarray[Any, Any], list[str]]:
-        raise NotImplementedError
+        """
+        Embed nodes using the specified algorithm.
+        Currently, only node2vec is supported but never called.
+        
+        Args:
+            algorithm: The name of the embedding algorithm to use
+            
+        Returns:
+            A tuple of (embeddings, node_ids)
+            
+        Raises:
+            NotImplementedError: If the specified algorithm is not supported
+            ValueError: If the algorithm is not supported
+        """
+        if algorithm not in self._node_embed_algorithms:
+            raise ValueError(f"Node embedding algorithm {algorithm} not supported")
+        return await self._node_embed_algorithms[algorithm]()
 
     async def get_all_labels(self) -> list[str]:
-        raise NotImplementedError
+        """
+        Get all node entity_names in the graph
+        Returns:
+            [entity_name1, entity_name2, ...]  # Alphabetically sorted entity_name list
+        """
+        query = f"""g
+                 .V().has('graph', {self.graph_name})
+                 .values('entity_name')
+                 .dedup()
+                 .order()
+                 """
+        try:
+            result = await self._query(query)
+            labels = result if result else []
+            logger.debug(
+                "{%s}: Retrieved %d labels",
+                inspect.currentframe().f_code.co_name,
+                len(labels)
+            )
+            return labels
+        except Exception as e:
+            logger.error(f"Error retrieving labels: {str(e)}")
+            return []
 
     async def get_knowledge_graph(
         self, node_label: str, max_depth: int = 5
     ) -> KnowledgeGraph:
-        raise NotImplementedError
+        """
+        Retrieve a connected subgraph of nodes where the entity_name includes the specified `node_label`.
+        Maximum number of nodes is constrained by the environment variable `MAX_GRAPH_NODES` (default: 1000).
+        
+        Args:
+            node_label: Entity name of the starting node
+            max_depth: Maximum depth of the subgraph
+
+        Returns:
+            KnowledgeGraph object containing nodes and edges
+        """
+        result = KnowledgeGraph()
+        seen_nodes = set()
+        seen_edges = set()
+        
+        # Get maximum number of graph nodes from environment variable, default is 1000
+        MAX_GRAPH_NODES = int(os.getenv("MAX_GRAPH_NODES", 1000))
+        
+        entity_name = GremlinStorage._fix_name(node_label)
+        
+        # Handle special case for "*" label
+        if node_label == "*":
+            # For "*", get all nodes and their edges (limited by MAX_GRAPH_NODES)
+            query = f"""g
+                     .V().has('graph', {self.graph_name})
+                     .limit({MAX_GRAPH_NODES})
+                     .elementMap()
+                     """
+            nodes_result = await self._query(query)
+            
+            # Add nodes to result
+            for node_data in nodes_result:
+                node_id = node_data.get('entity_name', str(node_data.get('id', '')))
+                if str(node_id) in seen_nodes:
+                    continue
+                
+                # Create node with properties
+                node_properties = {k: v for k, v in node_data.items() if k not in ['id', 'label']}
+                
+                result.nodes.append(
+                    KnowledgeGraphNode(
+                        id=str(node_id),
+                        labels=[str(node_id)], 
+                        properties=node_properties
+                    )
+                )
+                seen_nodes.add(str(node_id))
+            
+            # Get and add edges
+            if nodes_result:
+                query = f"""g
+                         .V().has('graph', {self.graph_name})
+                         .limit({MAX_GRAPH_NODES})
+                         .outE()
+                         .inV().has('graph', {self.graph_name})
+                         .limit({MAX_GRAPH_NODES})
+                         .path()
+                         .by(elementMap())
+                         .by(elementMap())
+                         .by(elementMap())
+                         """
+                edges_result = await self._query(query)
+                
+                for path in edges_result:
+                    if len(path) >= 3:  # source -> edge -> target
+                        source = path[0]
+                        edge_data = path[1]
+                        target = path[2]
+                        
+                        source_id = source.get('entity_name', str(source.get('id', '')))
+                        target_id = target.get('entity_name', str(target.get('id', '')))
+                        
+                        edge_id = f"{source_id}-{target_id}"
+                        if edge_id in seen_edges:
+                            continue
+                        
+                        # Create edge with properties
+                        edge_properties = {k: v for k, v in edge_data.items() if k not in ['id', 'label']}
+                        
+                        result.edges.append(
+                            KnowledgeGraphEdge(
+                                id=edge_id,
+                                type="DIRECTED",
+                                source=str(source_id),
+                                target=str(target_id),
+                                properties=edge_properties
+                            )
+                        )
+                        seen_edges.add(edge_id)
+        else:
+            # Search for specific node and get its neighborhood
+            query = f"""g
+                     .V().has('graph', {self.graph_name})
+                     .has('entity_name', {entity_name})
+                     .repeat(__.both().simplePath().dedup())
+                     .times({max_depth})
+                     .emit()
+                     .dedup()
+                     .limit({MAX_GRAPH_NODES})
+                     .elementMap()
+                     """
+            nodes_result = await self._query(query)
+            
+            # Add nodes to result
+            for node_data in nodes_result:
+                node_id = node_data.get('entity_name', str(node_data.get('id', '')))
+                if str(node_id) in seen_nodes:
+                    continue
+                
+                # Create node with properties
+                node_properties = {k: v for k, v in node_data.items() if k not in ['id', 'label']}
+                
+                result.nodes.append(
+                    KnowledgeGraphNode(
+                        id=str(node_id),
+                        labels=[str(node_id)], 
+                        properties=node_properties
+                    )
+                )
+                seen_nodes.add(str(node_id))
+            
+            # Get edges between the nodes in the result
+            if nodes_result:
+                node_ids = [n.get('entity_name', str(n.get('id', ''))) for n in nodes_result]
+                node_ids_query = ", ".join([GremlinStorage._to_value_map(nid) for nid in node_ids])
+                
+                query = f"""g
+                         .V().has('graph', {self.graph_name})
+                         .has('entity_name', within({node_ids_query}))
+                         .outE()
+                         .where(inV().has('graph', {self.graph_name})
+                                .has('entity_name', within({node_ids_query})))
+                         .path()
+                         .by(elementMap())
+                         .by(elementMap())
+                         .by(elementMap())
+                         """
+                edges_result = await self._query(query)
+                
+                for path in edges_result:
+                    if len(path) >= 3:  # source -> edge -> target
+                        source = path[0]
+                        edge_data = path[1]
+                        target = path[2]
+                        
+                        source_id = source.get('entity_name', str(source.get('id', '')))
+                        target_id = target.get('entity_name', str(target.get('id', '')))
+                        
+                        edge_id = f"{source_id}-{target_id}"
+                        if edge_id in seen_edges:
+                            continue
+                        
+                        # Create edge with properties
+                        edge_properties = {k: v for k, v in edge_data.items() if k not in ['id', 'label']}
+                        
+                        result.edges.append(
+                            KnowledgeGraphEdge(
+                                id=edge_id,
+                                type="DIRECTED",
+                                source=str(source_id),
+                                target=str(target_id),
+                                properties=edge_properties
+                            )
+                        )
+                        seen_edges.add(edge_id)
+        
+        logger.info(
+            "Subgraph query successful | Node count: %d | Edge count: %d",
+            len(result.nodes),
+            len(result.edges)
+        )
+        return result
+
+    async def remove_nodes(self, nodes: list[str]):
+        """Delete multiple nodes
+
+        Args:
+            nodes: List of node entity_names to be deleted
+        """
+        for node in nodes:
+            await self.delete_node(node)
+
+    async def remove_edges(self, edges: list[tuple[str, str]]):
+        """Delete multiple edges
+
+        Args:
+            edges: List of edges to be deleted, each edge is a (source, target) tuple
+        """
+        for source, target in edges:
+            entity_name_source = GremlinStorage._fix_name(source)
+            entity_name_target = GremlinStorage._fix_name(target)
+            
+            query = f"""g
+                     .V().has('graph', {self.graph_name})
+                     .has('entity_name', {entity_name_source})
+                     .outE()
+                     .where(inV().has('graph', {self.graph_name})
+                            .has('entity_name', {entity_name_target}))
+                     .drop()
+                     """
+            try:
+                await self._query(query)
+                logger.debug(
+                    "{%s}: Deleted edge from '%s' to '%s'",
+                    inspect.currentframe().f_code.co_name,
+                    entity_name_source,
+                    entity_name_target
+                )
+            except Exception as e:
+                logger.error(f"Error during edge deletion: {str(e)}")
+                raise

lightrag/kg/milvus_impl.py

@@ -3,7 +3,7 @@ import os
 from typing import Any, final
 from dataclasses import dataclass
 import numpy as np
-from lightrag.utils import logger
+from lightrag.utils import logger, compute_mdhash_id
 from ..base import BaseVectorStorage
 import pipmaster as pm
 
@@ -124,7 +124,84 @@ class MilvusVectorDBStorage(BaseVectorStorage):
         pass
 
     async def delete_entity(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete an entity from the vector database
+        
+        Args:
+            entity_name: The name of the entity to delete
+        """
+        try:
+            # Compute entity ID from name
+            entity_id = compute_mdhash_id(entity_name, prefix="ent-")
+            logger.debug(f"Attempting to delete entity {entity_name} with ID {entity_id}")
+            
+            # Delete the entity from Milvus collection
+            result = self._client.delete(
+                collection_name=self.namespace,
+                pks=[entity_id]
+            )
+            
+            if result and result.get("delete_count", 0) > 0:
+                logger.debug(f"Successfully deleted entity {entity_name}")
+            else:
+                logger.debug(f"Entity {entity_name} not found in storage")
+                
+        except Exception as e:
+            logger.error(f"Error deleting entity {entity_name}: {e}")
 
     async def delete_entity_relation(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete all relations associated with an entity
+        
+        Args:
+            entity_name: The name of the entity whose relations should be deleted
+        """
+        try:
+            # Search for relations where entity is either source or target
+            expr = f'src_id == "{entity_name}" or tgt_id == "{entity_name}"'
+            
+            # Find all relations involving this entity
+            results = self._client.query(
+                collection_name=self.namespace,
+                filter=expr,
+                output_fields=["id"]
+            )
+            
+            if not results or len(results) == 0:
+                logger.debug(f"No relations found for entity {entity_name}")
+                return
+                
+            # Extract IDs of relations to delete
+            relation_ids = [item["id"] for item in results]
+            logger.debug(f"Found {len(relation_ids)} relations for entity {entity_name}")
+            
+            # Delete the relations
+            if relation_ids:
+                delete_result = self._client.delete(
+                    collection_name=self.namespace,
+                    pks=relation_ids
+                )
+                
+                logger.debug(f"Deleted {delete_result.get('delete_count', 0)} relations for {entity_name}")
+                
+        except Exception as e:
+            logger.error(f"Error deleting relations for {entity_name}: {e}")
+
+    async def delete(self, ids: list[str]) -> None:
+        """Delete vectors with specified IDs
+        
+        Args:
+            ids: List of vector IDs to be deleted
+        """
+        try:
+            # Delete vectors by IDs
+            result = self._client.delete(
+                collection_name=self.namespace,
+                pks=ids
+            )
+            
+            if result and result.get("delete_count", 0) > 0:
+                logger.debug(f"Successfully deleted {result.get('delete_count', 0)} vectors from {self.namespace}")
+            else:
+                logger.debug(f"No vectors were deleted from {self.namespace}")
+                
+        except Exception as e:
+            logger.error(f"Error while deleting vectors from {self.namespace}: {e}")

lightrag/kg/mongo_impl.py

@@ -15,7 +15,7 @@ from ..base import (
     DocStatusStorage,
 )
 from ..namespace import NameSpace, is_namespace
-from ..utils import logger
+from ..utils import logger, compute_mdhash_id
 from ..types import KnowledgeGraph, KnowledgeGraphNode, KnowledgeGraphEdge
 import pipmaster as pm
 
@@ -333,7 +333,7 @@ class MongoGraphStorage(BaseGraphStorage):
         Check if there's a direct single-hop edge from source_node_id to target_node_id.
 
         We'll do a $graphLookup with maxDepth=0 from the source node—meaning
-        “Look up zero expansions.” Actually, for a direct edge check, we can do maxDepth=1
+        "Look up zero expansions." Actually, for a direct edge check, we can do maxDepth=1
         and then see if the target node is in the "reachableNodes" at depth=0.
 
         But typically for a direct edge, we might just do a find_one.
@@ -795,6 +795,52 @@ class MongoGraphStorage(BaseGraphStorage):
         # Mongo handles persistence automatically
         pass
 
+    async def remove_nodes(self, nodes: list[str]) -> None:
+        """Delete multiple nodes
+
+        Args:
+            nodes: List of node IDs to be deleted
+        """
+        logger.info(f"Deleting {len(nodes)} nodes")
+        if not nodes:
+            return
+        
+        # 1. Remove all edges referencing these nodes (remove from edges array of other nodes)
+        await self.collection.update_many(
+            {}, 
+            {"$pull": {"edges": {"target": {"$in": nodes}}}}
+        )
+        
+        # 2. Delete the node documents
+        await self.collection.delete_many({"_id": {"$in": nodes}})
+        
+        logger.debug(f"Successfully deleted nodes: {nodes}")
+
+    async def remove_edges(self, edges: list[tuple[str, str]]) -> None:
+        """Delete multiple edges
+
+        Args:
+            edges: List of edges to be deleted, each edge is a (source, target) tuple
+        """
+        logger.info(f"Deleting {len(edges)} edges")
+        if not edges:
+            return
+        
+        update_tasks = []
+        for source, target in edges:
+            # Remove edge pointing to target from source node's edges array
+            update_tasks.append(
+                self.collection.update_one(
+                    {"_id": source},
+                    {"$pull": {"edges": {"target": target}}}
+                )
+            )
+        
+        if update_tasks:
+            await asyncio.gather(*update_tasks)
+            
+        logger.debug(f"Successfully deleted edges: {edges}")
+
 
 @final
 @dataclass
@@ -932,11 +978,66 @@ class MongoVectorDBStorage(BaseVectorStorage):
         # Mongo handles persistence automatically
         pass
 
+    async def delete(self, ids: list[str]) -> None:
+        """Delete vectors with specified IDs
+
+        Args:
+            ids: List of vector IDs to be deleted
+        """
+        logger.info(f"Deleting {len(ids)} vectors from {self.namespace}")
+        if not ids:
+            return
+        
+        try:
+            result = await self._data.delete_many({"_id": {"$in": ids}})
+            logger.debug(f"Successfully deleted {result.deleted_count} vectors from {self.namespace}")
+        except PyMongoError as e:
+            logger.error(f"Error while deleting vectors from {self.namespace}: {str(e)}")
+
     async def delete_entity(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete an entity by its name
+        
+        Args:
+            entity_name: Name of the entity to delete
+        """
+        try:
+            entity_id = compute_mdhash_id(entity_name, prefix="ent-")
+            logger.debug(f"Attempting to delete entity {entity_name} with ID {entity_id}")
+            
+            result = await self._data.delete_one({"_id": entity_id})
+            if result.deleted_count > 0:
+                logger.debug(f"Successfully deleted entity {entity_name}")
+            else:
+                logger.debug(f"Entity {entity_name} not found in storage")
+        except PyMongoError as e:
+            logger.error(f"Error deleting entity {entity_name}: {str(e)}")
 
     async def delete_entity_relation(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete all relations associated with an entity
+        
+        Args:
+            entity_name: Name of the entity whose relations should be deleted
+        """
+        try:
+            # Find relations where entity appears as source or target
+            relations_cursor = self._data.find(
+                {"$or": [{"src_id": entity_name}, {"tgt_id": entity_name}]}
+            )
+            relations = await relations_cursor.to_list(length=None)
+            
+            if not relations:
+                logger.debug(f"No relations found for entity {entity_name}")
+                return
+            
+            # Extract IDs of relations to delete
+            relation_ids = [relation["_id"] for relation in relations]
+            logger.debug(f"Found {len(relation_ids)} relations for entity {entity_name}")
+            
+            # Delete the relations
+            result = await self._data.delete_many({"_id": {"$in": relation_ids}})
+            logger.debug(f"Deleted {result.deleted_count} relations for {entity_name}")
+        except PyMongoError as e:
+            logger.error(f"Error deleting relations for {entity_name}: {str(e)}")
 
 
 async def get_or_create_collection(db: AsyncIOMotorDatabase, collection_name: str):

lightrag/kg/oracle_impl.py

@@ -8,7 +8,7 @@ from typing import Any, Union, final
 import numpy as np
 import configparser
 
-from lightrag.types import KnowledgeGraph
+from lightrag.types import KnowledgeGraph, KnowledgeGraphNode, KnowledgeGraphEdge
 
 from ..base import (
     BaseGraphStorage,
@@ -442,11 +442,55 @@ class OracleVectorDBStorage(BaseVectorStorage):
         # Oracles handles persistence automatically
         pass
 
+    async def delete(self, ids: list[str]) -> None:
+        """Delete vectors with specified IDs
+        
+        Args:
+            ids: List of vector IDs to be deleted
+        """
+        if not ids:
+            return
+            
+        try:
+            SQL = SQL_TEMPLATES["delete_vectors"].format(
+                ids=",".join([f"'{id}'" for id in ids])
+            )
+            params = {"workspace": self.db.workspace}
+            await self.db.execute(SQL, params)
+            logger.info(f"Successfully deleted {len(ids)} vectors from {self.namespace}")
+        except Exception as e:
+            logger.error(f"Error while deleting vectors from {self.namespace}: {e}")
+            raise
+
     async def delete_entity(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete entity by name
+        
+        Args:
+            entity_name: Name of the entity to delete
+        """
+        try:
+            SQL = SQL_TEMPLATES["delete_entity"]
+            params = {"workspace": self.db.workspace, "entity_name": entity_name}
+            await self.db.execute(SQL, params)
+            logger.info(f"Successfully deleted entity {entity_name}")
+        except Exception as e:
+            logger.error(f"Error deleting entity {entity_name}: {e}")
+            raise
 
     async def delete_entity_relation(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete all relations connected to an entity
+        
+        Args:
+            entity_name: Name of the entity whose relations should be deleted
+        """
+        try:
+            SQL = SQL_TEMPLATES["delete_entity_relations"]
+            params = {"workspace": self.db.workspace, "entity_name": entity_name}
+            await self.db.execute(SQL, params)
+            logger.info(f"Successfully deleted relations for entity {entity_name}")
+        except Exception as e:
+            logger.error(f"Error deleting relations for entity {entity_name}: {e}")
+            raise
 
 
 @final
@@ -668,15 +712,206 @@ class OracleGraphStorage(BaseGraphStorage):
             return res
 
     async def delete_node(self, node_id: str) -> None:
-        raise NotImplementedError
+        """Delete a node from the graph
+        
+        Args:
+            node_id: ID of the node to delete
+        """
+        try:
+            # First delete all relations connected to this node
+            delete_relations_sql = SQL_TEMPLATES["delete_entity_relations"]
+            params_relations = {"workspace": self.db.workspace, "entity_name": node_id}
+            await self.db.execute(delete_relations_sql, params_relations)
+            
+            # Then delete the node itself
+            delete_node_sql = SQL_TEMPLATES["delete_entity"]
+            params_node = {"workspace": self.db.workspace, "entity_name": node_id}
+            await self.db.execute(delete_node_sql, params_node)
+            
+            logger.info(f"Successfully deleted node {node_id} and all its relationships")
+        except Exception as e:
+            logger.error(f"Error deleting node {node_id}: {e}")
+            raise
 
     async def get_all_labels(self) -> list[str]:
-        raise NotImplementedError
+        """Get all unique entity types (labels) in the graph
+        
+        Returns:
+            List of unique entity types/labels
+        """
+        try:
+            SQL = """
+                SELECT DISTINCT entity_type 
+                FROM LIGHTRAG_GRAPH_NODES 
+                WHERE workspace = :workspace 
+                ORDER BY entity_type
+            """
+            params = {"workspace": self.db.workspace}
+            results = await self.db.query(SQL, params, multirows=True)
+            
+            if results:
+                labels = [row["entity_type"] for row in results]
+                return labels
+            else:
+                return []
+        except Exception as e:
+            logger.error(f"Error retrieving entity types: {e}")
+            return []
 
     async def get_knowledge_graph(
         self, node_label: str, max_depth: int = 5
     ) -> KnowledgeGraph:
-        raise NotImplementedError
+        """Retrieve a connected subgraph starting from nodes matching the given label
+        
+        Maximum number of nodes is constrained by MAX_GRAPH_NODES environment variable.
+        Prioritizes nodes by:
+        1. Nodes matching the specified label
+        2. Nodes directly connected to matching nodes
+        3. Node degree (number of connections)
+        
+        Args:
+            node_label: Label to match for starting nodes (use "*" for all nodes)
+            max_depth: Maximum depth of traversal from starting nodes
+            
+        Returns:
+            KnowledgeGraph object containing nodes and edges
+        """
+        result = KnowledgeGraph()
+        
+        try:
+            # Define maximum number of nodes to return
+            max_graph_nodes = int(os.environ.get("MAX_GRAPH_NODES", 1000))
+            
+            if node_label == "*":
+                # For "*" label, get all nodes up to the limit
+                nodes_sql = """
+                    SELECT name, entity_type, description, source_chunk_id
+                    FROM LIGHTRAG_GRAPH_NODES
+                    WHERE workspace = :workspace
+                    ORDER BY id
+                    FETCH FIRST :limit ROWS ONLY
+                """
+                nodes_params = {"workspace": self.db.workspace, "limit": max_graph_nodes}
+                nodes = await self.db.query(nodes_sql, nodes_params, multirows=True)
+            else:
+                # For specific label, find matching nodes and related nodes
+                nodes_sql = """
+                    WITH matching_nodes AS (
+                        SELECT name 
+                        FROM LIGHTRAG_GRAPH_NODES
+                        WHERE workspace = :workspace 
+                        AND (name LIKE '%' || :node_label || '%' OR entity_type LIKE '%' || :node_label || '%')
+                    )
+                    SELECT n.name, n.entity_type, n.description, n.source_chunk_id,
+                           CASE
+                               WHEN n.name IN (SELECT name FROM matching_nodes) THEN 2
+                               WHEN EXISTS (
+                                   SELECT 1 FROM LIGHTRAG_GRAPH_EDGES e 
+                                   WHERE workspace = :workspace
+                                   AND ((e.source_name = n.name AND e.target_name IN (SELECT name FROM matching_nodes))
+                                      OR (e.target_name = n.name AND e.source_name IN (SELECT name FROM matching_nodes)))
+                               ) THEN 1
+                               ELSE 0
+                           END AS priority,
+                           (SELECT COUNT(*) FROM LIGHTRAG_GRAPH_EDGES e 
+                            WHERE workspace = :workspace 
+                            AND (e.source_name = n.name OR e.target_name = n.name)) AS degree
+                    FROM LIGHTRAG_GRAPH_NODES n
+                    WHERE workspace = :workspace
+                    ORDER BY priority DESC, degree DESC
+                    FETCH FIRST :limit ROWS ONLY
+                """
+                nodes_params = {
+                    "workspace": self.db.workspace, 
+                    "node_label": node_label,
+                    "limit": max_graph_nodes
+                }
+                nodes = await self.db.query(nodes_sql, nodes_params, multirows=True)
+            
+            if not nodes:
+                logger.warning(f"No nodes found matching '{node_label}'")
+                return result
+                
+            # Create mapping of node IDs to be used to filter edges
+            node_names = [node["name"] for node in nodes]
+            
+            # Add nodes to result
+            seen_nodes = set()
+            for node in nodes:
+                node_id = node["name"]
+                if node_id in seen_nodes:
+                    continue
+                    
+                # Create node properties dictionary
+                properties = {
+                    "entity_type": node["entity_type"],
+                    "description": node["description"] or "",
+                    "source_id": node["source_chunk_id"] or ""
+                }
+                
+                # Add node to result
+                result.nodes.append(
+                    KnowledgeGraphNode(
+                        id=node_id,
+                        labels=[node["entity_type"]],
+                        properties=properties
+                    )
+                )
+                seen_nodes.add(node_id)
+            
+            # Get edges between these nodes
+            edges_sql = """
+                SELECT source_name, target_name, weight, keywords, description, source_chunk_id
+                FROM LIGHTRAG_GRAPH_EDGES
+                WHERE workspace = :workspace
+                AND source_name IN (SELECT COLUMN_VALUE FROM TABLE(CAST(:node_names AS SYS.ODCIVARCHAR2LIST)))
+                AND target_name IN (SELECT COLUMN_VALUE FROM TABLE(CAST(:node_names AS SYS.ODCIVARCHAR2LIST)))
+                ORDER BY id
+            """
+            edges_params = {
+                "workspace": self.db.workspace,
+                "node_names": node_names
+            }
+            edges = await self.db.query(edges_sql, edges_params, multirows=True)
+            
+            # Add edges to result
+            seen_edges = set()
+            for edge in edges:
+                source = edge["source_name"]
+                target = edge["target_name"]
+                edge_id = f"{source}-{target}"
+                
+                if edge_id in seen_edges:
+                    continue
+                
+                # Create edge properties dictionary
+                properties = {
+                    "weight": edge["weight"] or 0.0,
+                    "keywords": edge["keywords"] or "",
+                    "description": edge["description"] or "",
+                    "source_id": edge["source_chunk_id"] or ""
+                }
+                
+                # Add edge to result
+                result.edges.append(
+                    KnowledgeGraphEdge(
+                        id=edge_id,
+                        type="RELATED",
+                        source=source,
+                        target=target,
+                        properties=properties
+                    )
+                )
+                seen_edges.add(edge_id)
+            
+            logger.info(
+                f"Subgraph query successful | Node count: {len(result.nodes)} | Edge count: {len(result.edges)}"
+            )
+            
+        except Exception as e:
+            logger.error(f"Error retrieving knowledge graph: {e}")
+        
+        return result
 
 
 N_T = {
@@ -927,4 +1162,12 @@ SQL_TEMPLATES = {
                 select 'edge' as type, TO_CHAR(id) id FROM GRAPH_TABLE (lightrag_graph
                     MATCH (a)-[e]->(b) WHERE e.workspace=:workspace columns(e.id))
                 )""",
+    # SQL for deletion
+    "delete_vectors": "DELETE FROM LIGHTRAG_DOC_CHUNKS WHERE workspace=:workspace AND id IN ({ids})",
+    "delete_entity": "DELETE FROM LIGHTRAG_GRAPH_NODES WHERE workspace=:workspace AND name=:entity_name",
+    "delete_entity_relations": "DELETE FROM LIGHTRAG_GRAPH_EDGES WHERE workspace=:workspace AND (source_name=:entity_name OR target_name=:entity_name)",
+    "delete_node": """DELETE FROM GRAPH_TABLE (lightrag_graph 
+        MATCH (a) 
+        WHERE a.workspace=:workspace AND a.name=:node_id 
+        ACTION DELETE a)""",
 }

lightrag/kg/postgres_impl.py

@@ -7,7 +7,7 @@ from typing import Any, Union, final
 import numpy as np
 import configparser
 
-from lightrag.types import KnowledgeGraph
+from lightrag.types import KnowledgeGraph, KnowledgeGraphNode, KnowledgeGraphEdge
 
 import sys
 from tenacity import (
@@ -512,11 +512,66 @@ class PGVectorStorage(BaseVectorStorage):
         # PG handles persistence automatically
         pass
 
+    async def delete(self, ids: list[str]) -> None:
+        """Delete vectors with specified IDs from the storage.
+
+        Args:
+            ids: List of vector IDs to be deleted
+        """
+        if not ids:
+            return
+
+        table_name = namespace_to_table_name(self.namespace)
+        if not table_name:
+            logger.error(f"Unknown namespace for vector deletion: {self.namespace}")
+            return
+
+        ids_list = ",".join([f"'{id}'" for id in ids])
+        delete_sql = f"DELETE FROM {table_name} WHERE workspace=$1 AND id IN ({ids_list})"
+        
+        try:
+            await self.db.execute(delete_sql, {"workspace": self.db.workspace})
+            logger.debug(f"Successfully deleted {len(ids)} vectors from {self.namespace}")
+        except Exception as e:
+            logger.error(f"Error while deleting vectors from {self.namespace}: {e}")
+
     async def delete_entity(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete an entity by its name from the vector storage.
+
+        Args:
+            entity_name: The name of the entity to delete
+        """
+        try:
+            # Construct SQL to delete the entity
+            delete_sql = """DELETE FROM LIGHTRAG_VDB_ENTITY 
+                            WHERE workspace=$1 AND entity_name=$2"""
+            
+            await self.db.execute(
+                delete_sql, 
+                {"workspace": self.db.workspace, "entity_name": entity_name}
+            )
+            logger.debug(f"Successfully deleted entity {entity_name}")
+        except Exception as e:
+            logger.error(f"Error deleting entity {entity_name}: {e}")
 
     async def delete_entity_relation(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete all relations associated with an entity.
+
+        Args:
+            entity_name: The name of the entity whose relations should be deleted
+        """
+        try:
+            # Delete relations where the entity is either the source or target
+            delete_sql = """DELETE FROM LIGHTRAG_VDB_RELATION 
+                            WHERE workspace=$1 AND (source_id=$2 OR target_id=$2)"""
+            
+            await self.db.execute(
+                delete_sql, 
+                {"workspace": self.db.workspace, "entity_name": entity_name}
+            )
+            logger.debug(f"Successfully deleted relations for entity {entity_name}")
+        except Exception as e:
+            logger.error(f"Error deleting relations for entity {entity_name}: {e}")
 
 
 @final
@@ -1086,20 +1141,192 @@ class PGGraphStorage(BaseGraphStorage):
         print("Implemented but never called.")
 
     async def delete_node(self, node_id: str) -> None:
-        raise NotImplementedError
+        """
+        Delete a node from the graph.
+
+        Args:
+            node_id (str): The ID of the node to delete.
+        """
+        label = self._encode_graph_label(node_id.strip('"'))
+
+        query = """SELECT * FROM cypher('%s', $$
+                     MATCH (n:Entity {node_id: "%s"})
+                     DETACH DELETE n
+                   $$) AS (n agtype)""" % (self.graph_name, label)
+
+        try:
+            await self._query(query, readonly=False)
+        except Exception as e:
+            logger.error("Error during node deletion: {%s}", e)
+            raise
+
+    async def remove_nodes(self, node_ids: list[str]) -> None:
+        """
+        Remove multiple nodes from the graph.
+
+        Args:
+            node_ids (list[str]): A list of node IDs to remove.
+        """
+        encoded_node_ids = [self._encode_graph_label(node_id.strip('"')) for node_id in node_ids]
+        node_id_list = ", ".join([f'"{node_id}"' for node_id in encoded_node_ids])
+
+        query = """SELECT * FROM cypher('%s', $$
+                     MATCH (n:Entity)
+                     WHERE n.node_id IN [%s]
+                     DETACH DELETE n
+                   $$) AS (n agtype)""" % (self.graph_name, node_id_list)
+
+        try:
+            await self._query(query, readonly=False)
+        except Exception as e:
+            logger.error("Error during node removal: {%s}", e)
+            raise
+
+    async def remove_edges(self, edges: list[tuple[str, str]]) -> None:
+        """
+        Remove multiple edges from the graph.
+
+        Args:
+            edges (list[tuple[str, str]]): A list of edges to remove, where each edge is a tuple of (source_node_id, target_node_id).
+        """
+        encoded_edges = [(self._encode_graph_label(src.strip('"')), self._encode_graph_label(tgt.strip('"'))) for src, tgt in edges]
+        edge_list = ", ".join([f'["{src}", "{tgt}"]' for src, tgt in encoded_edges])
+
+        query = """SELECT * FROM cypher('%s', $$
+                     MATCH (a:Entity)-[r]->(b:Entity)
+                     WHERE [a.node_id, b.node_id] IN [%s]
+                     DELETE r
+                   $$) AS (r agtype)""" % (self.graph_name, edge_list)
+
+        try:
+            await self._query(query, readonly=False)
+        except Exception as e:
+            logger.error("Error during edge removal: {%s}", e)
+            raise
+
+    async def get_all_labels(self) -> list[str]:
+        """
+        Get all labels (node IDs) in the graph.
+
+        Returns:
+            list[str]: A list of all labels in the graph.
+        """
+        query = """SELECT * FROM cypher('%s', $$
+                     MATCH (n:Entity)
+                     RETURN DISTINCT n.node_id AS label
+                   $$) AS (label text)""" % self.graph_name
+
+        results = await self._query(query)
+        labels = [self._decode_graph_label(result["label"]) for result in results]
+
+        return labels
 
     async def embed_nodes(
         self, algorithm: str
     ) -> tuple[np.ndarray[Any, Any], list[str]]:
-        raise NotImplementedError
+        """
+        Generate node embeddings using the specified algorithm.
 
-    async def get_all_labels(self) -> list[str]:
-        raise NotImplementedError
+        Args:
+            algorithm (str): The name of the embedding algorithm to use.
+
+        Returns:
+            tuple[np.ndarray[Any, Any], list[str]]: A tuple containing the embeddings and the corresponding node IDs.
+        """
+        if algorithm not in self._node_embed_algorithms:
+            raise ValueError(f"Unsupported embedding algorithm: {algorithm}")
+
+        embed_func = self._node_embed_algorithms[algorithm]
+        return await embed_func()
 
     async def get_knowledge_graph(
         self, node_label: str, max_depth: int = 5
     ) -> KnowledgeGraph:
-        raise NotImplementedError
+        """
+        Retrieve a subgraph containing the specified node and its neighbors up to the specified depth.
+
+        Args:
+            node_label (str): The label of the node to start from. If "*", the entire graph is returned.
+            max_depth (int): The maximum depth to traverse from the starting node.
+
+        Returns:
+            KnowledgeGraph: The retrieved subgraph.
+        """
+        MAX_GRAPH_NODES = 1000
+
+        if node_label == "*":
+            query = """SELECT * FROM cypher('%s', $$
+                         MATCH (n:Entity)
+                         OPTIONAL MATCH (n)-[r]->(m:Entity)
+                         RETURN n, r, m
+                         LIMIT %d
+                       $$) AS (n agtype, r agtype, m agtype)""" % (self.graph_name, MAX_GRAPH_NODES)
+        else:
+            encoded_node_label = self._encode_graph_label(node_label.strip('"'))
+            query = """SELECT * FROM cypher('%s', $$
+                         MATCH (n:Entity {node_id: "%s"})
+                         OPTIONAL MATCH p = (n)-[*..%d]-(m)
+                         RETURN nodes(p) AS nodes, relationships(p) AS relationships
+                         LIMIT %d
+                       $$) AS (nodes agtype[], relationships agtype[])""" % (self.graph_name, encoded_node_label, max_depth, MAX_GRAPH_NODES)
+
+        results = await self._query(query)
+
+        nodes = set()
+        edges = []
+
+        for result in results:
+            if node_label == "*":
+                if result["n"]:
+                    node = result["n"]
+                    nodes.add(self._decode_graph_label(node["node_id"]))
+                if result["m"]:
+                    node = result["m"]
+                    nodes.add(self._decode_graph_label(node["node_id"]))
+                if result["r"]:
+                    edge = result["r"]
+                    src_id = self._decode_graph_label(edge["start_id"])
+                    tgt_id = self._decode_graph_label(edge["end_id"])
+                    edges.append((src_id, tgt_id))
+            else:
+                if result["nodes"]:
+                    for node in result["nodes"]:
+                        nodes.add(self._decode_graph_label(node["node_id"]))
+                if result["relationships"]:
+                    for edge in result["relationships"]:
+                        src_id = self._decode_graph_label(edge["start_id"])
+                        tgt_id = self._decode_graph_label(edge["end_id"])
+                        edges.append((src_id, tgt_id))
+
+        kg = KnowledgeGraph(
+            nodes=[KnowledgeGraphNode(id=node_id) for node_id in nodes],
+            edges=[KnowledgeGraphEdge(source=src, target=tgt) for src, tgt in edges],
+        )
+
+        return kg
+
+    async def get_all_labels(self) -> list[str]:
+        """
+        Get all node labels in the graph
+        Returns:
+            [label1, label2, ...] # Alphabetically sorted label list
+        """
+        query = """SELECT * FROM cypher('%s', $$
+                     MATCH (n:Entity)
+                     RETURN DISTINCT n.node_id AS label
+                     ORDER BY label
+                   $$) AS (label agtype)""" % (self.graph_name)
+        
+        try:
+            results = await self._query(query)
+            labels = []
+            for record in results:
+                if record["label"]:
+                    labels.append(self._decode_graph_label(record["label"]))
+            return labels
+        except Exception as e:
+            logger.error(f"Error getting all labels: {str(e)}")
+            return []
 
     async def drop(self) -> None:
         """Drop the storage"""

lightrag/kg/qdrant_impl.py

@@ -1,6 +1,6 @@
 import asyncio
 import os
-from typing import Any, final
+from typing import Any, final, List
 from dataclasses import dataclass
 import numpy as np
 import hashlib
@@ -141,8 +141,91 @@ class QdrantVectorDBStorage(BaseVectorStorage):
         # Qdrant handles persistence automatically
         pass
 
+    async def delete(self, ids: List[str]) -> None:
+        """Delete vectors with specified IDs
+        
+        Args:
+            ids: List of vector IDs to be deleted
+        """
+        try:
+            # Convert regular ids to Qdrant compatible ids
+            qdrant_ids = [compute_mdhash_id_for_qdrant(id) for id in ids]
+            # Delete points from the collection
+            self._client.delete(
+                collection_name=self.namespace,
+                points_selector=models.PointIdsList(
+                    points=qdrant_ids,
+                ),
+                wait=True
+            )
+            logger.debug(f"Successfully deleted {len(ids)} vectors from {self.namespace}")
+        except Exception as e:
+            logger.error(f"Error while deleting vectors from {self.namespace}: {e}")
+
     async def delete_entity(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete an entity by name
+        
+        Args:
+            entity_name: Name of the entity to delete
+        """
+        try:
+            # Generate the entity ID
+            entity_id = compute_mdhash_id_for_qdrant(entity_name, prefix="ent-")
+            logger.debug(f"Attempting to delete entity {entity_name} with ID {entity_id}")
+            
+            # Delete the entity point from the collection
+            self._client.delete(
+                collection_name=self.namespace,
+                points_selector=models.PointIdsList(
+                    points=[entity_id],
+                ),
+                wait=True
+            )
+            logger.debug(f"Successfully deleted entity {entity_name}")
+        except Exception as e:
+            logger.error(f"Error deleting entity {entity_name}: {e}")
 
     async def delete_entity_relation(self, entity_name: str) -> None:
-        raise NotImplementedError
+        """Delete all relations associated with an entity
+        
+        Args:
+            entity_name: Name of the entity whose relations should be deleted
+        """
+        try:
+            # Find relations where the entity is either source or target
+            results = self._client.scroll(
+                collection_name=self.namespace,
+                scroll_filter=models.Filter(
+                    should=[
+                        models.FieldCondition(
+                            key="src_id",
+                            match=models.MatchValue(value=entity_name)
+                        ),
+                        models.FieldCondition(
+                            key="tgt_id",
+                            match=models.MatchValue(value=entity_name)
+                        )
+                    ]
+                ),
+                with_payload=True,
+                limit=1000  # Adjust as needed for your use case
+            )
+            
+            # Extract points that need to be deleted
+            relation_points = results[0]
+            ids_to_delete = [point.id for point in relation_points]
+            
+            if ids_to_delete:
+                # Delete the relations
+                self._client.delete(
+                    collection_name=self.namespace,
+                    points_selector=models.PointIdsList(
+                        points=ids_to_delete,
+                    ),
+                    wait=True
+                )
+                logger.debug(f"Deleted {len(ids_to_delete)} relations for {entity_name}")
+            else:
+                logger.debug(f"No relations found for entity {entity_name}")
+        except Exception as e:
+            logger.error(f"Error deleting relations for {entity_name}: {e}")

lightrag/kg/redis_impl.py

@@ -9,7 +9,7 @@ if not pm.is_installed("redis"):
 
 # aioredis is a depricated library, replaced with redis
 from redis.asyncio import Redis
-from lightrag.utils import logger
+from lightrag.utils import logger, compute_mdhash_id
 from lightrag.base import BaseKVStorage
 import json
 
@@ -64,3 +64,79 @@ class RedisKVStorage(BaseKVStorage):
     async def index_done_callback(self) -> None:
         # Redis handles persistence automatically
         pass
+
+    async def delete(self, ids: list[str]) -> None:
+        """Delete entries with specified IDs
+        
+        Args:
+            ids: List of entry IDs to be deleted
+        """
+        if not ids:
+            return
+        
+        pipe = self._redis.pipeline()
+        for id in ids:
+            pipe.delete(f"{self.namespace}:{id}")
+        
+        results = await pipe.execute()
+        deleted_count = sum(results)
+        logger.info(f"Deleted {deleted_count} of {len(ids)} entries from {self.namespace}")
+
+    async def delete_entity(self, entity_name: str) -> None:
+        """Delete an entity by name
+        
+        Args:
+            entity_name: Name of the entity to delete
+        """
+        
+        try:
+            entity_id = compute_mdhash_id(entity_name, prefix="ent-")
+            logger.debug(f"Attempting to delete entity {entity_name} with ID {entity_id}")
+            
+            # Delete the entity
+            result = await self._redis.delete(f"{self.namespace}:{entity_id}")
+            
+            if result:
+                logger.debug(f"Successfully deleted entity {entity_name}")
+            else:
+                logger.debug(f"Entity {entity_name} not found in storage")
+        except Exception as e:
+            logger.error(f"Error deleting entity {entity_name}: {e}")
+
+    async def delete_entity_relation(self, entity_name: str) -> None:
+        """Delete all relations associated with an entity
+        
+        Args:
+            entity_name: Name of the entity whose relations should be deleted
+        """
+        try:
+            # Get all keys in this namespace
+            cursor = 0
+            relation_keys = []
+            pattern = f"{self.namespace}:*"
+            
+            while True:
+                cursor, keys = await self._redis.scan(cursor, match=pattern)
+                
+                # For each key, get the value and check if it's related to entity_name
+                for key in keys:
+                    value = await self._redis.get(key)
+                    if value:
+                        data = json.loads(value)
+                        # Check if this is a relation involving the entity
+                        if data.get("src_id") == entity_name or data.get("tgt_id") == entity_name:
+                            relation_keys.append(key)
+                
+                # Exit loop when cursor returns to 0
+                if cursor == 0:
+                    break
+            
+            # Delete the relation keys
+            if relation_keys:
+                deleted = await self._redis.delete(*relation_keys)
+                logger.debug(f"Deleted {deleted} relations for {entity_name}")
+            else:
+                logger.debug(f"No relations found for entity {entity_name}")
+                
+        except Exception as e:
+            logger.error(f"Error deleting relations for {entity_name}: {e}")

lightrag/kg/tidb_impl.py

@@ -5,7 +5,7 @@ from typing import Any, Union, final
 
 import numpy as np
 
-from lightrag.types import KnowledgeGraph
+from lightrag.types import KnowledgeGraph, KnowledgeGraphNode, KnowledgeGraphEdge
 
 
 from ..base import BaseGraphStorage, BaseKVStorage, BaseVectorStorage
@@ -566,15 +566,148 @@ class TiDBGraphStorage(BaseGraphStorage):
         pass
 
     async def delete_node(self, node_id: str) -> None:
-        raise NotImplementedError
-
+        """Delete a node and all its related edges
+        
+        Args:
+            node_id: The ID of the node to delete
+        """
+        # First delete all edges related to this node
+        await self.db.execute(SQL_TEMPLATES["delete_node_edges"], 
+                            {"name": node_id, "workspace": self.db.workspace})
+        
+        # Then delete the node itself
+        await self.db.execute(SQL_TEMPLATES["delete_node"], 
+                            {"name": node_id, "workspace": self.db.workspace})
+        
+        logger.debug(f"Node {node_id} and its related edges have been deleted from the graph")
+    
     async def get_all_labels(self) -> list[str]:
-        raise NotImplementedError
-
+        """Get all entity types (labels) in the database
+        
+        Returns:
+            List of labels sorted alphabetically
+        """
+        result = await self.db.query(
+            SQL_TEMPLATES["get_all_labels"], 
+            {"workspace": self.db.workspace}, 
+            multirows=True
+        )
+        
+        if not result:
+            return []
+        
+        # Extract all labels
+        return [item["label"] for item in result]
+    
     async def get_knowledge_graph(
         self, node_label: str, max_depth: int = 5
     ) -> KnowledgeGraph:
-        raise NotImplementedError
+        """
+        Get a connected subgraph of nodes matching the specified label
+        Maximum number of nodes is limited by MAX_GRAPH_NODES environment variable (default: 1000)
+        
+        Args:
+            node_label: The node label to match
+            max_depth: Maximum depth of the subgraph
+            
+        Returns:
+            KnowledgeGraph object containing nodes and edges
+        """
+        result = KnowledgeGraph()
+        MAX_GRAPH_NODES = int(os.getenv("MAX_GRAPH_NODES", 1000))
+        
+        # Get matching nodes
+        if node_label == "*":
+            # Handle special case, get all nodes
+            node_results = await self.db.query(
+                SQL_TEMPLATES["get_all_nodes"],
+                {"workspace": self.db.workspace, "max_nodes": MAX_GRAPH_NODES},
+                multirows=True
+            )
+        else:
+            # Get nodes matching the label
+            label_pattern = f"%{node_label}%"
+            node_results = await self.db.query(
+                SQL_TEMPLATES["get_matching_nodes"],
+                {"workspace": self.db.workspace, "label_pattern": label_pattern},
+                multirows=True
+            )
+            
+        if not node_results:
+            logger.warning(f"No nodes found matching label {node_label}")
+            return result
+            
+        # Limit the number of returned nodes
+        if len(node_results) > MAX_GRAPH_NODES:
+            node_results = node_results[:MAX_GRAPH_NODES]
+            
+        # Extract node names for edge query
+        node_names = [node["name"] for node in node_results]
+        node_names_str = ",".join([f"'{name}'" for name in node_names])
+        
+        # Add nodes to result
+        for node in node_results:
+            node_properties = {k: v for k, v in node.items() if k not in ["id", "name", "entity_type"]}
+            result.nodes.append(
+                KnowledgeGraphNode(
+                    id=node["name"],
+                    labels=[node["entity_type"]] if node.get("entity_type") else [node["name"]],
+                    properties=node_properties
+                )
+            )
+            
+        # Get related edges
+        edge_results = await self.db.query(
+            SQL_TEMPLATES["get_related_edges"].format(node_names=node_names_str),
+            {"workspace": self.db.workspace},
+            multirows=True
+        )
+        
+        if edge_results:
+            # Add edges to result
+            for edge in edge_results:
+                # Only include edges related to selected nodes
+                if edge["source_name"] in node_names and edge["target_name"] in node_names:
+                    edge_id = f"{edge['source_name']}-{edge['target_name']}"
+                    edge_properties = {k: v for k, v in edge.items() 
+                                    if k not in ["id", "source_name", "target_name"]}
+                    
+                    result.edges.append(
+                        KnowledgeGraphEdge(
+                            id=edge_id,
+                            type="RELATED",
+                            source=edge["source_name"],
+                            target=edge["target_name"],
+                            properties=edge_properties
+                        )
+                    )
+                
+        logger.info(
+            f"Subgraph query successful | Node count: {len(result.nodes)} | Edge count: {len(result.edges)}"
+        )
+        return result
+    
+    async def remove_nodes(self, nodes: list[str]):
+        """Delete multiple nodes
+        
+        Args:
+            nodes: List of node IDs to delete
+        """
+        for node_id in nodes:
+            await self.delete_node(node_id)
+            
+    async def remove_edges(self, edges: list[tuple[str, str]]):
+        """Delete multiple edges
+        
+        Args:
+            edges: List of edges to delete, each edge is a (source, target) tuple
+        """
+        for source, target in edges:
+            await self.db.execute(SQL_TEMPLATES["remove_multiple_edges"], {
+                "source": source,
+                "target": target,
+                "workspace": self.db.workspace
+            })
 
 
 N_T = {
@@ -785,4 +918,39 @@ SQL_TEMPLATES = {
         weight = VALUES(weight), keywords = VALUES(keywords), description = VALUES(description),
         source_chunk_id = VALUES(source_chunk_id)
     """,
+    "delete_node": """
+        DELETE FROM LIGHTRAG_GRAPH_NODES 
+        WHERE name = :name AND workspace = :workspace
+    """,
+    "delete_node_edges": """
+        DELETE FROM LIGHTRAG_GRAPH_EDGES 
+        WHERE (source_name = :name OR target_name = :name) AND workspace = :workspace
+    """,
+    "get_all_labels": """
+        SELECT DISTINCT entity_type as label 
+        FROM LIGHTRAG_GRAPH_NODES 
+        WHERE workspace = :workspace
+        ORDER BY entity_type
+    """,
+    "get_matching_nodes": """
+        SELECT * FROM LIGHTRAG_GRAPH_NODES 
+        WHERE name LIKE :label_pattern AND workspace = :workspace
+        ORDER BY name
+    """,
+    "get_all_nodes": """
+        SELECT * FROM LIGHTRAG_GRAPH_NODES 
+        WHERE workspace = :workspace
+        ORDER BY name
+        LIMIT :max_nodes
+    """,
+    "get_related_edges": """
+        SELECT * FROM LIGHTRAG_GRAPH_EDGES
+        WHERE (source_name IN (:node_names) OR target_name IN (:node_names))
+        AND workspace = :workspace
+    """,
+    "remove_multiple_edges": """
+        DELETE FROM LIGHTRAG_GRAPH_EDGES
+        WHERE (source_name = :source AND target_name = :target)
+        AND workspace = :workspace
+    """
 }

lightrag/lightrag.py

@@ -1399,6 +1399,54 @@ class LightRAG:
             ]
         )
 
+    def delete_by_relation(self, source_entity: str, target_entity: str) -> None:
+        """Synchronously delete a relation between two entities.
+        
+        Args:
+            source_entity: Name of the source entity
+            target_entity: Name of the target entity
+        """
+        loop = always_get_an_event_loop()
+        return loop.run_until_complete(self.adelete_by_relation(source_entity, target_entity))
+
+    async def adelete_by_relation(self, source_entity: str, target_entity: str) -> None:
+        """Asynchronously delete a relation between two entities.
+        
+        Args:
+            source_entity: Name of the source entity
+            target_entity: Name of the target entity
+        """
+        try:
+            # Check if the relation exists
+            edge_exists = await self.chunk_entity_relation_graph.has_edge(source_entity, target_entity)
+            if not edge_exists:
+                logger.warning(f"Relation from '{source_entity}' to '{target_entity}' does not exist")
+                return
+            
+            # Delete relation from vector database
+            relation_id = compute_mdhash_id(source_entity + target_entity, prefix="rel-")
+            await self.relationships_vdb.delete([relation_id])
+            
+            # Delete relation from knowledge graph
+            await self.chunk_entity_relation_graph.remove_edges([(source_entity, target_entity)])
+            
+            logger.info(f"Successfully deleted relation from '{source_entity}' to '{target_entity}'")
+            await self._delete_relation_done()
+        except Exception as e:
+            logger.error(f"Error while deleting relation from '{source_entity}' to '{target_entity}': {e}")
+    
+    async def _delete_relation_done(self) -> None:
+        """Callback after relation deletion is complete"""
+        await asyncio.gather(
+            *[
+                cast(StorageNameSpace, storage_inst).index_done_callback()
+                for storage_inst in [  # type: ignore
+                    self.relationships_vdb,
+                    self.chunk_entity_relation_graph,
+                ]
+            ]
+        )
+
     def _get_content_summary(self, content: str, max_length: int = 100) -> str:
         """Get summary of document content