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| from langchain_community.graphs.neo4j_graph import Neo4jGraph | |
| SCHEMA_QUERY = """ | |
| CALL llm_util.schema("raw") | |
| YIELD * | |
| RETURN * | |
| """ | |
| class MemgraphGraph(Neo4jGraph): | |
| """Memgraph wrapper for graph operations. | |
| *Security note*: Make sure that the database connection uses credentials | |
| that are narrowly-scoped to only include necessary permissions. | |
| Failure to do so may result in data corruption or loss, since the calling | |
| code may attempt commands that would result in deletion, mutation | |
| of data if appropriately prompted or reading sensitive data if such | |
| data is present in the database. | |
| The best way to guard against such negative outcomes is to (as appropriate) | |
| limit the permissions granted to the credentials used with this tool. | |
| See https://python.langchain.com/docs/security for more information. | |
| """ | |
| def __init__( | |
| self, url: str, username: str, password: str, *, database: str = "memgraph" | |
| ) -> None: | |
| """Create a new Memgraph graph wrapper instance.""" | |
| super().__init__(url, username, password, database=database) | |
| def refresh_schema(self) -> None: | |
| """ | |
| Refreshes the Memgraph graph schema information. | |
| """ | |
| db_structured_schema = self.query(SCHEMA_QUERY)[0].get("schema") | |
| assert db_structured_schema is not None | |
| self.structured_schema = db_structured_schema | |
| # Format node properties | |
| formatted_node_props = [] | |
| for node_name, properties in db_structured_schema["node_props"].items(): | |
| formatted_node_props.append( | |
| f"Node name: '{node_name}', Node properties: {properties}" | |
| ) | |
| # Format relationship properties | |
| formatted_rel_props = [] | |
| for rel_name, properties in db_structured_schema["rel_props"].items(): | |
| formatted_rel_props.append( | |
| f"Relationship name: '{rel_name}', " | |
| f"Relationship properties: {properties}" | |
| ) | |
| # Format relationships | |
| formatted_rels = [ | |
| f"(:{rel['start']})-[:{rel['type']}]->(:{rel['end']})" | |
| for rel in db_structured_schema["relationships"] | |
| ] | |
| self.schema = "\n".join( | |
| [ | |
| "Node properties are the following:", | |
| *formatted_node_props, | |
| "Relationship properties are the following:", | |
| *formatted_rel_props, | |
| "The relationships are the following:", | |
| *formatted_rels, | |
| ] | |
| ) | |