add support for querying all nodes and relationships in Neo4j

lightrag/kg/neo4j_impl.py

@@ -382,6 +382,15 @@ class Neo4JStorage(BaseGraphStorage):
 
         async with self._driver.session(database=self._DATABASE) as session:
             try:
+                main_query = ""
+                if label == '*':
+                    main_query = """
+                    MATCH (n)
+                    WITH collect(DISTINCT n) AS nodes
+                    MATCH ()-[r]-()
+                    RETURN nodes, collect(DISTINCT r) AS relationships;
+                    """
+                else:
                     # Critical debug step: first verify if starting node exists
                     validate_query = f"MATCH (n:`{label}`) RETURN n LIMIT 1"
                     validate_result = await session.run(validate_query)
@@ -409,28 +418,29 @@ class Neo4JStorage(BaseGraphStorage):
                     # Handle nodes (compatible with multi-label cases)
                     for node in record["nodes"]:
                         # Use node ID + label combination as unique identifier
-                        node_id = f"{node.id}_{'_'.join(node.labels)}"
+                        node_id = node.id
                         if node_id not in seen_nodes:
-                            node_data = dict(node)
+                            node_data = {}
                             node_data["labels"] = list(node.labels)  # Keep all labels
+                            node_data["id"] = f"{node_id}"
+                            node_data["properties"] = dict(node)
                             result["nodes"].append(node_data)
                             seen_nodes.add(node_id)
 
                     # Handle relationships (including direction information)
                     for rel in record["relationships"]:
-                        edge_id = f"{rel.id}_{rel.type}"
+                        edge_id = rel.id
                         if edge_id not in seen_edges:
                             start = rel.start_node
                             end = rel.end_node
-                            edge_data = dict(rel)
+                            edge_data = {}
                             edge_data.update(
                                 {
-                                    "source": f"{start.id}_{'_'.join(start.labels)}",
-                                    "target": f"{end.id}_{'_'.join(end.labels)}",
+                                    "source": f"{start.id}",
+                                    "target": f"{end.id}",
                                     "type": rel.type,
-                                    "direction": rel.element_id.split(
-                                        "->" if rel.end_node == end else "<-"
-                                    )[1],
+                                    "id": f"{edge_id}",
+                                    "properties": dict(rel),
                                 }
                             )
                             result["edges"].append(edge_data)