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适用于 Apache Gremlin 的 Azure Cosmos DB 是一种图数据库服务,可用于存储包含数十亿个顶点和边的海量图。您可以通过毫秒级延迟查询图并轻松演进图结构。 Gremlin 是由 Apache Software FoundationApache TinkerPop 开发的一种图遍历语言和虚拟机。
本笔记本演示了如何使用 LLM 提供一个自然语言接口,用于查询可使用 Gremlin 查询语言进行查询的图数据库。

设置

安装库
!pip3 install gremlinpython
您将需要一个 Azure CosmosDB 图数据库实例。一种选择是在 Azure 中创建一个免费的 CosmosDB 图数据库实例 创建 Cosmos DB 帐户和图时,请使用 /type 作为分区键。
cosmosdb_name = "mycosmosdb"
cosmosdb_db_id = "graphtesting"
cosmosdb_db_graph_id = "mygraph"
cosmosdb_access_Key = "longstring=="
import nest_asyncio
from langchain_community.chains.graph_qa.gremlin import GremlinQAChain
from langchain_community.graphs import GremlinGraph
from langchain_community.graphs.graph_document import GraphDocument, Node, Relationship
from langchain_core.documents import Document
from langchain_openai import AzureChatOpenAI
graph = GremlinGraph(
    url=f"wss://{cosmosdb_name}.gremlin.cosmos.azure.com:443/",
    username=f"/dbs/{cosmosdb_db_id}/colls/{cosmosdb_db_graph_id}",
    password=cosmosdb_access_Key,
)

数据库初始化

假设您的数据库为空,您可以使用 GraphDocuments 填充它。 对于 Gremlin,始终为每个节点添加一个名为“label”的属性。如果未设置标签,则使用 Node.type 作为标签。对于 Cosmos,使用自然 ID 更有意义,因为它们在图浏览器中可见。
source_doc = Document(
    page_content="Matrix is a movie where Keanu Reeves, Laurence Fishburne and Carrie-Anne Moss acted."
)
movie = Node(id="The Matrix", properties={"label": "movie", "title": "The Matrix"})
actor1 = Node(id="Keanu Reeves", properties={"label": "actor", "name": "Keanu Reeves"})
actor2 = Node(
    id="Laurence Fishburne", properties={"label": "actor", "name": "Laurence Fishburne"}
)
actor3 = Node(
    id="Carrie-Anne Moss", properties={"label": "actor", "name": "Carrie-Anne Moss"}
)
rel1 = Relationship(
    id=5, type="ActedIn", source=actor1, target=movie, properties={"label": "ActedIn"}
)
rel2 = Relationship(
    id=6, type="ActedIn", source=actor2, target=movie, properties={"label": "ActedIn"}
)
rel3 = Relationship(
    id=7, type="ActedIn", source=actor3, target=movie, properties={"label": "ActedIn"}
)
rel4 = Relationship(
    id=8,
    type="Starring",
    source=movie,
    target=actor1,
    properties={"label": "Strarring"},
)
rel5 = Relationship(
    id=9,
    type="Starring",
    source=movie,
    target=actor2,
    properties={"label": "Strarring"},
)
rel6 = Relationship(
    id=10,
    type="Straring",
    source=movie,
    target=actor3,
    properties={"label": "Strarring"},
)
graph_doc = GraphDocument(
    nodes=[movie, actor1, actor2, actor3],
    relationships=[rel1, rel2, rel3, rel4, rel5, rel6],
    source=source_doc,
)
# The underlying python-gremlin has a problem when running in notebook
# The following line is a workaround to fix the problem
nest_asyncio.apply()

# Add the document to the CosmosDB graph.
graph.add_graph_documents([graph_doc])

刷新图模式信息

如果数据库模式发生更改(更新后),您可以刷新模式信息。
graph.refresh_schema()
print(graph.schema)

查询图

现在我们可以使用 gremlin QA 链来询问图的问题
chain = GremlinQAChain.from_llm(
    AzureChatOpenAI(
        temperature=0,
        azure_deployment="gpt-4-turbo",
    ),
    graph=graph,
    verbose=True,
)
chain.invoke("Who played in The Matrix?")
chain.run("How many people played in The Matrix?")

以编程方式连接这些文档到 Claude、VSCode 等,通过 MCP 获取实时答案。
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