Graph RAG với LangChain và Neo4j
Adam Cowley
Manager, Developer Education at Neo4j


Giới thiệu:
The Project Gutenberg eBook of Romeo and Juliet
This ebook is for the use of anyone anywhere in the United States and
most other parts of the world at no cost and with almost no restrictions
Title: Romeo and Juliet
Author: William Shakespeare
Thông tin nhân vật:
Dramatis Personæ
ESCALUS, Prince of Verona.
MERCUTIO, kinsman to the Prince, and friend to Romeo.
PARIS, a young Nobleman, kinsman to the Prince.
Page to Paris.
...
Dẫn nhập:
Enter Chorus.
CHORUS.
Two households, both alike in dignity,
In fair Verona, where we lay our scene,
From ancient grudge break to new mutiny,
...
Hồi và Cảnh:
ACT I
SCENE I. A public place.
Enter Sampson and Gregory armed with swords and bucklers.
SAMPSON.
Gregory, on my word, we’ll not carry coals.
GREGORY.
No, for then we should be colliers...




→ Mỗi nút Lời thoại sẽ có thuộc tính văn bản và embedding

Nạp tài liệu vào bộ nhớ bằng bộ nạp tài liệu:
# Load the PDF
loader = PyPDFLoader("romeo-and-juliet.pdf")
pages = loader.load()
act_splitter = RecursiveCharacterTextSplitter( # Split text into acts separators=[ r"\n\nTHE PROLOGUE.", r"\n\nACT", r"\n\n\*\*\* END"], is_separator_regex=True )scene_splitter = RecursiveCharacterTextSplitter( # Split act into scenes separators=[r"\nSCENE "], is_separator_regex=True )
play = Node(type="Play",id="romeo-and-juliet",properties={ "title": "Romeo and Juliet", "playwright": "William Shakespeare", "genres": ["Romance", "Tragedy"] })# Store in a graph document graph_doc = GraphDocument(nodes=[play], relationships=[])
parts = act_splitter.split_text(text)for act in parts: print(act[:20])
THE PROLOGUE...ACT IACT IIACT III
parts = act_splitter.split_text(text) for a, act in enumerate(parts):first_line = act_text.split("\n")[0].strip()if first_line.startswith("ACT"):act_node = Node(type="Act",id=first_line,)graph_doc.nodes.append(act_node)
for a, act in enumerate(parts): # ... # act_node = Node(...)# Create a relationship relationship = Relationship(source=play,target=act_node,type="HAS_ACT",properties=dict(order=a))graph_doc.relationships.append(relationship)
Dùng đối tượng Neo4jGraph:
graph = Neo4jGraph(
url=NEO4J_URI,
username=NEO4J_USERNAME,
password=NEO4J_PASSWORD
)
graph.add_graph_documents([graph_doc])
Graph RAG với LangChain và Neo4j