Neo4jvector

Neo4jVectorStore

Bases: BasePydanticVectorStore

Neo4j Vector Store.

Examples:

pip install llama-index-vector-stores-neo4jvector

from llama_index.vector_stores.neo4jvector import Neo4jVectorStore

username = "neo4j"
password = "pleaseletmein"
url = "bolt://localhost:7687"
embed_dim = 1536

neo4j_vector = Neo4jVectorStore(username, password, url, embed_dim)

Source code in llama-index-integrations/vector_stores/llama-index-vector-stores-neo4jvector/llama_index/vector_stores/neo4jvector/base.py

class Neo4jVectorStore(BasePydanticVectorStore):
    """Neo4j Vector Store.

    Examples:
        `pip install llama-index-vector-stores-neo4jvector`


        ```python
        from llama_index.vector_stores.neo4jvector import Neo4jVectorStore

        username = "neo4j"
        password = "pleaseletmein"
        url = "bolt://localhost:7687"
        embed_dim = 1536

        neo4j_vector = Neo4jVectorStore(username, password, url, embed_dim)
        ```
    """

    stores_text: bool = True
    flat_metadata: bool = True

    distance_strategy: str
    index_name: str
    keyword_index_name: str
    hybrid_search: bool
    node_label: str
    embedding_node_property: str
    text_node_property: str
    retrieval_query: str
    embedding_dimension: int

    _driver: neo4j.GraphDatabase.driver = PrivateAttr()
    _database: str = PrivateAttr()
    _support_metadata_filter: bool = PrivateAttr()
    _is_enterprise: bool = PrivateAttr()

    def __init__(
        self,
        username: str,
        password: str,
        url: str,
        embedding_dimension: int,
        database: str = "neo4j",
        index_name: str = "vector",
        keyword_index_name: str = "keyword",
        node_label: str = "Chunk",
        embedding_node_property: str = "embedding",
        text_node_property: str = "text",
        distance_strategy: str = "cosine",
        hybrid_search: bool = False,
        retrieval_query: str = "",
        **kwargs: Any,
    ) -> None:
        super().__init__(
            distance_strategy=distance_strategy,
            index_name=index_name,
            keyword_index_name=keyword_index_name,
            hybrid_search=hybrid_search,
            node_label=node_label,
            embedding_node_property=embedding_node_property,
            text_node_property=text_node_property,
            retrieval_query=retrieval_query,
            embedding_dimension=embedding_dimension,
        )

        if distance_strategy not in ["cosine", "euclidean"]:
            raise ValueError("distance_strategy must be either 'euclidean' or 'cosine'")

        self._driver = neo4j.GraphDatabase.driver(url, auth=(username, password))
        self._database = database

        # Verify connection
        try:
            self._driver.verify_connectivity()
        except neo4j.exceptions.ServiceUnavailable:
            raise ValueError(
                "Could not connect to Neo4j database. "
                "Please ensure that the url is correct"
            )
        except neo4j.exceptions.AuthError:
            raise ValueError(
                "Could not connect to Neo4j database. "
                "Please ensure that the username and password are correct"
            )

        # Verify if the version support vector index
        self._verify_version()

        # Verify that required values are not null
        check_if_not_null(
            [
                "index_name",
                "node_label",
                "embedding_node_property",
                "text_node_property",
            ],
            [index_name, node_label, embedding_node_property, text_node_property],
        )

        index_already_exists = self.retrieve_existing_index()
        if not index_already_exists:
            self.create_new_index()
        if hybrid_search:
            fts_node_label = self.retrieve_existing_fts_index()
            # If the FTS index doesn't exist yet
            if not fts_node_label:
                self.create_new_keyword_index()
            else:  # Validate that FTS and Vector index use the same information
                if not fts_node_label == self.node_label:
                    raise ValueError(
                        "Vector and keyword index don't index the same node label"
                    )

    @property
    def client(self) -> neo4j.GraphDatabase.driver:
        return self._driver

    def _verify_version(self) -> None:
        """
        Check if the connected Neo4j database version supports vector indexing.

        Queries the Neo4j database to retrieve its version and compares it
        against a target version (5.11.0) that is known to support vector
        indexing. Raises a ValueError if the connected Neo4j version is
        not supported.
        """
        db_data = self.database_query("CALL dbms.components()")
        version = db_data[0]["versions"][0]
        if "aura" in version:
            version_tuple = (*tuple(map(int, version.split("-")[0].split("."))), 0)
        else:
            version_tuple = tuple(map(int, version.split(".")))

        target_version = (5, 11, 0)

        if version_tuple < target_version:
            raise ValueError(
                "Version index is only supported in Neo4j version 5.11 or greater"
            )

        # Flag for metadata filtering
        metadata_target_version = (5, 18, 0)
        if version_tuple < metadata_target_version:
            self._support_metadata_filter = False
        else:
            self._support_metadata_filter = True
        # Flag for enterprise
        self._is_enterprise = db_data[0]["edition"] == "enterprise"

    def create_new_index(self) -> None:
        """
        This method constructs a Cypher query and executes it
        to create a new vector index in Neo4j.
        """
        index_query = (
            "CALL db.index.vector.createNodeIndex("
            "$index_name,"
            "$node_label,"
            "$embedding_node_property,"
            "toInteger($embedding_dimension),"
            "$similarity_metric )"
        )

        parameters = {
            "index_name": self.index_name,
            "node_label": self.node_label,
            "embedding_node_property": self.embedding_node_property,
            "embedding_dimension": self.embedding_dimension,
            "similarity_metric": self.distance_strategy,
        }
        self.database_query(index_query, params=parameters)

    def retrieve_existing_index(self) -> bool:
        """
        Check if the vector index exists in the Neo4j database
        and returns its embedding dimension.

        This method queries the Neo4j database for existing indexes
        and attempts to retrieve the dimension of the vector index
        with the specified name. If the index exists, its dimension is returned.
        If the index doesn't exist, `None` is returned.

        Returns:
            int or None: The embedding dimension of the existing index if found.
        """
        index_information = self.database_query(
            "SHOW INDEXES YIELD name, type, labelsOrTypes, properties, options "
            "WHERE type = 'VECTOR' AND (name = $index_name "
            "OR (labelsOrTypes[0] = $node_label AND "
            "properties[0] = $embedding_node_property)) "
            "RETURN name, labelsOrTypes, properties, options ",
            params={
                "index_name": self.index_name,
                "node_label": self.node_label,
                "embedding_node_property": self.embedding_node_property,
            },
        )
        # sort by index_name
        index_information = sort_by_index_name(index_information, self.index_name)
        try:
            self.index_name = index_information[0]["name"]
            self.node_label = index_information[0]["labelsOrTypes"][0]
            self.embedding_node_property = index_information[0]["properties"][0]
            index_config = index_information[0]["options"]["indexConfig"]
            if "vector.dimensions" in index_config:
                self.embedding_dimension = index_config["vector.dimensions"]

            return True
        except IndexError:
            return False

    def retrieve_existing_fts_index(self) -> Optional[str]:
        """Check if the fulltext index exists in the Neo4j database.

        This method queries the Neo4j database for existing fts indexes
        with the specified name.

        Returns:
            (Tuple): keyword index information
        """
        index_information = self.database_query(
            "SHOW INDEXES YIELD name, type, labelsOrTypes, properties, options "
            "WHERE type = 'FULLTEXT' AND (name = $keyword_index_name "
            "OR (labelsOrTypes = [$node_label] AND "
            "properties = $text_node_property)) "
            "RETURN name, labelsOrTypes, properties, options ",
            params={
                "keyword_index_name": self.keyword_index_name,
                "node_label": self.node_label,
                "text_node_property": self.text_node_property,
            },
        )
        # sort by index_name
        index_information = sort_by_index_name(index_information, self.index_name)
        try:
            self.keyword_index_name = index_information[0]["name"]
            self.text_node_property = index_information[0]["properties"][0]
            return index_information[0]["labelsOrTypes"][0]
        except IndexError:
            return None

    def create_new_keyword_index(self, text_node_properties: List[str] = []) -> None:
        """
        This method constructs a Cypher query and executes it
        to create a new full text index in Neo4j.
        """
        node_props = text_node_properties or [self.text_node_property]
        fts_index_query = (
            f"CREATE FULLTEXT INDEX {self.keyword_index_name} "
            f"FOR (n:`{self.node_label}`) ON EACH "
            f"[{', '.join(['n.`' + el + '`' for el in node_props])}]"
        )
        self.database_query(fts_index_query)

    def database_query(
        self,
        query: str,
        params: Optional[Dict[str, Any]] = None,
    ) -> Any:
        params = params or {}
        try:
            data, _, _ = self._driver.execute_query(
                query, database_=self._database, parameters_=params
            )
            return [r.data() for r in data]
        except neo4j.exceptions.Neo4jError as e:
            if not (
                (
                    (  # isCallInTransactionError
                        e.code == "Neo.DatabaseError.Statement.ExecutionFailed"
                        or e.code
                        == "Neo.DatabaseError.Transaction.TransactionStartFailed"
                    )
                    and "in an implicit transaction" in e.message
                )
                or (  # isPeriodicCommitError
                    e.code == "Neo.ClientError.Statement.SemanticError"
                    and (
                        "in an open transaction is not possible" in e.message
                        or "tried to execute in an explicit transaction" in e.message
                    )
                )
            ):
                raise
        # Fallback to allow implicit transactions
        with self._driver.session(database=self._database) as session:
            data = session.run(neo4j.Query(text=query), params)
            return [r.data() for r in data]

    def add(self, nodes: List[BaseNode], **add_kwargs: Any) -> List[str]:
        ids = [r.node_id for r in nodes]
        import_query = (
            "UNWIND $data AS row "
            "CALL { WITH row "
            f"MERGE (c:`{self.node_label}` {{id: row.id}}) "
            "WITH c, row "
            f"CALL db.create.setVectorProperty(c, "
            f"'{self.embedding_node_property}', row.embedding) "
            "YIELD node "
            f"SET c.`{self.text_node_property}` = row.text "
            "SET c += row.metadata } IN TRANSACTIONS OF 1000 ROWS"
        )

        self.database_query(
            import_query,
            params={"data": clean_params(nodes)},
        )

        return ids

    def query(self, query: VectorStoreQuery, **kwargs: Any) -> VectorStoreQueryResult:
        if query.filters:
            # Verify that 5.18 or later is used
            if not self._support_metadata_filter:
                raise ValueError(
                    "Metadata filtering is only supported in "
                    "Neo4j version 5.18 or greater"
                )
            # Metadata filtering and hybrid doesn't work
            if self.hybrid_search:
                raise ValueError(
                    "Metadata filtering can't be use in combination with "
                    "a hybrid search approach"
                )
            parallel_query = (
                "CYPHER runtime = parallel parallelRuntimeSupport=all "
                if self._is_enterprise
                else ""
            )
            base_index_query = parallel_query + (
                f"MATCH (n:`{self.node_label}`) WHERE "
                f"n.`{self.embedding_node_property}` IS NOT NULL AND "
            )
            if self.embedding_dimension:
                base_index_query += (
                    f"size(n.`{self.embedding_node_property}`) = "
                    f"toInteger({self.embedding_dimension}) AND "
                )
            base_cosine_query = (
                " WITH n as node, vector.similarity.cosine("
                f"n.`{self.embedding_node_property}`, "
                "$embedding) AS score ORDER BY score DESC LIMIT toInteger($k) "
            )
            filter_snippets, filter_params = construct_metadata_filter(query.filters)
            index_query = base_index_query + filter_snippets + base_cosine_query
        else:
            index_query = _get_search_index_query(self.hybrid_search)
            filter_params = {}

        default_retrieval = (
            f"RETURN node.`{self.text_node_property}` AS text, score, "
            "node.id AS id, "
            f"node {{.*, `{self.text_node_property}`: Null, "
            f"`{self.embedding_node_property}`: Null, id: Null }} AS metadata"
        )

        retrieval_query = self.retrieval_query or default_retrieval
        read_query = index_query + retrieval_query

        parameters = {
            "index": self.index_name,
            "k": query.similarity_top_k,
            "embedding": query.query_embedding,
            "keyword_index": self.keyword_index_name,
            "query": remove_lucene_chars(query.query_str),
            **filter_params,
        }

        results = self.database_query(read_query, params=parameters)

        nodes = []
        similarities = []
        ids = []
        for record in results:
            node = metadata_dict_to_node(record["metadata"])
            node.set_content(str(record["text"]))
            nodes.append(node)
            similarities.append(record["score"])
            ids.append(record["id"])

        return VectorStoreQueryResult(nodes=nodes, similarities=similarities, ids=ids)

    def delete(self, ref_doc_id: str, **delete_kwargs: Any) -> None:
        self.database_query(
            f"MATCH (n:`{self.node_label}`) WHERE n.ref_doc_id = $id DETACH DELETE n",
            params={"id": ref_doc_id},
        )

create_new_index

create_new_index() -> None

This method constructs a Cypher query and executes it to create a new vector index in Neo4j.

Source code in llama-index-integrations/vector_stores/llama-index-vector-stores-neo4jvector/llama_index/vector_stores/neo4jvector/base.py

def create_new_index(self) -> None:
    """
    This method constructs a Cypher query and executes it
    to create a new vector index in Neo4j.
    """
    index_query = (
        "CALL db.index.vector.createNodeIndex("
        "$index_name,"
        "$node_label,"
        "$embedding_node_property,"
        "toInteger($embedding_dimension),"
        "$similarity_metric )"
    )

    parameters = {
        "index_name": self.index_name,
        "node_label": self.node_label,
        "embedding_node_property": self.embedding_node_property,
        "embedding_dimension": self.embedding_dimension,
        "similarity_metric": self.distance_strategy,
    }
    self.database_query(index_query, params=parameters)

retrieve_existing_index

retrieve_existing_index() -> bool

Check if the vector index exists in the Neo4j database and returns its embedding dimension.

This method queries the Neo4j database for existing indexes and attempts to retrieve the dimension of the vector index with the specified name. If the index exists, its dimension is returned. If the index doesn't exist, None is returned.

Returns:

Type	Description
bool	int or None: The embedding dimension of the existing index if found.

Source code in llama-index-integrations/vector_stores/llama-index-vector-stores-neo4jvector/llama_index/vector_stores/neo4jvector/base.py

def retrieve_existing_index(self) -> bool:
    """
    Check if the vector index exists in the Neo4j database
    and returns its embedding dimension.

    This method queries the Neo4j database for existing indexes
    and attempts to retrieve the dimension of the vector index
    with the specified name. If the index exists, its dimension is returned.
    If the index doesn't exist, `None` is returned.

    Returns:
        int or None: The embedding dimension of the existing index if found.
    """
    index_information = self.database_query(
        "SHOW INDEXES YIELD name, type, labelsOrTypes, properties, options "
        "WHERE type = 'VECTOR' AND (name = $index_name "
        "OR (labelsOrTypes[0] = $node_label AND "
        "properties[0] = $embedding_node_property)) "
        "RETURN name, labelsOrTypes, properties, options ",
        params={
            "index_name": self.index_name,
            "node_label": self.node_label,
            "embedding_node_property": self.embedding_node_property,
        },
    )
    # sort by index_name
    index_information = sort_by_index_name(index_information, self.index_name)
    try:
        self.index_name = index_information[0]["name"]
        self.node_label = index_information[0]["labelsOrTypes"][0]
        self.embedding_node_property = index_information[0]["properties"][0]
        index_config = index_information[0]["options"]["indexConfig"]
        if "vector.dimensions" in index_config:
            self.embedding_dimension = index_config["vector.dimensions"]

        return True
    except IndexError:
        return False

retrieve_existing_fts_index

retrieve_existing_fts_index() -> Optional[str]

Check if the fulltext index exists in the Neo4j database.

This method queries the Neo4j database for existing fts indexes with the specified name.

Returns:

Type	Description
Tuple	keyword index information

Source code in llama-index-integrations/vector_stores/llama-index-vector-stores-neo4jvector/llama_index/vector_stores/neo4jvector/base.py

def retrieve_existing_fts_index(self) -> Optional[str]:
    """Check if the fulltext index exists in the Neo4j database.

    This method queries the Neo4j database for existing fts indexes
    with the specified name.

    Returns:
        (Tuple): keyword index information
    """
    index_information = self.database_query(
        "SHOW INDEXES YIELD name, type, labelsOrTypes, properties, options "
        "WHERE type = 'FULLTEXT' AND (name = $keyword_index_name "
        "OR (labelsOrTypes = [$node_label] AND "
        "properties = $text_node_property)) "
        "RETURN name, labelsOrTypes, properties, options ",
        params={
            "keyword_index_name": self.keyword_index_name,
            "node_label": self.node_label,
            "text_node_property": self.text_node_property,
        },
    )
    # sort by index_name
    index_information = sort_by_index_name(index_information, self.index_name)
    try:
        self.keyword_index_name = index_information[0]["name"]
        self.text_node_property = index_information[0]["properties"][0]
        return index_information[0]["labelsOrTypes"][0]
    except IndexError:
        return None

create_new_keyword_index

create_new_keyword_index(text_node_properties: List[str] = []) -> None

This method constructs a Cypher query and executes it to create a new full text index in Neo4j.

Source code in llama-index-integrations/vector_stores/llama-index-vector-stores-neo4jvector/llama_index/vector_stores/neo4jvector/base.py

def create_new_keyword_index(self, text_node_properties: List[str] = []) -> None:
    """
    This method constructs a Cypher query and executes it
    to create a new full text index in Neo4j.
    """
    node_props = text_node_properties or [self.text_node_property]
    fts_index_query = (
        f"CREATE FULLTEXT INDEX {self.keyword_index_name} "
        f"FOR (n:`{self.node_label}`) ON EACH "
        f"[{', '.join(['n.`' + el + '`' for el in node_props])}]"
    )
    self.database_query(fts_index_query)