Building a text-to-Cypher chain

You've written you're own Cypher queries, so let's try using LLMs to generate them! Generating a Cypher query from a user query in natural language is a key part of a text-to-Cypher Graph RAG workflow.

You're working with the same database as the previous exercise, containing nodes that represent people, companies, and WORKS_FOR relationships available as graph.

This exercise is part of the course

Graph RAG with LangChain and Neo4j

Exercise instructions

Update the partial_variables dictionary to insert the graph schema into the prompt.
Create the text-to-Cypher chain using the prompt, llm, and parsing to a string.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

prompt = ChatPromptTemplate.from_messages([
    SystemMessagePromptTemplate.from_template(""" 
		You are an expert Neo4j developer. Use the following database schema to write a Cypher statement to answer the user's question. Only generate the Cypher statement, no pre-amble. Do not return any Markdown.
	Schema: 
    {schema}
    
	Question: {question}""", 
	# Update the partial_variables dictionary
    partial_variables={"schema": graph.____})
])

# Create the text-to-Cypher chain
text_to_cypher_chain = ____ | ____ | StrOutputParser()
cypher = text_to_cypher_chain.invoke({"question": "Where does Jo Cornelissen work?"})
print(cypher)

Edit and Run Code

This exercise is part of the course

Graph RAG with LangChain and Neo4j

AdvancedSkill Level

4.9+

Start Course for Free

Learn how Graph RAG can improve the accuracy and reliability of RAG applications! Store information as nodes and edges in a Neo4j database, and give your LLM the ability to query it so it can retrieve entity and relational information to provide informed answers.

Exercise 1: Graphs and RAG Exercise 2: Creating nodes Exercise 3: Creating relationships Exercise 4: Saving graph documents Exercise 5: Querying a knowledge graph Exercise 6: Writing Cypher statements Exercise 7: Running Cypher statements Exercise 8: The MERGE clause Exercise 9: Text-to-Cypher Graph RAG with Neo4j Exercise 10: Building a text-to-Cypher chain

Current Exercise

Exercise 11: Text-to-Cypher retrieval chain

Text-to-Cypher applications work well in many circumstances, but we can do better than that! Discover how to construct graph databases using different graph models including lexical and domain graphs. Create Neo4j vector indexes so that you can have the best of both worlds and run graph and vector retrieval simultaneously!

Exercise 1: Lexical graphs Exercise 2: Elements of a lexical graph Exercise 3: Splitting the play into Acts Exercise 4: Creating a hierarchical lexical graph Exercise 5: Combining lexical graphs with vector search Exercise 6: Creating text chunks Exercise 7: Creating a vector index Exercise 8: Domain graphs Exercise 9: Creating a structured output Exercise 10: Requesting a structured output Exercise 11: Providing few-shot examples Exercise 12: Building a hybrid retrieval chain Exercise 13: Runnable lambdas Exercise 14: Assigning additional values to an input Exercise 15: The final link in the chain

Although Graph RAG applications are generally more reliable than vector RAG, they aren't totally infallible. In this chapter, you'll learn to evaluate your Graph RAG applications, spot incorrect or duplicate graph nodes, and integrate long-term memory so user preferences can be learned over time.

Exercise 1: Entity resolution Exercise 2: Using extracted entities Exercise 3: Graph-based entity resolution Exercise 4: Evaluating Graph RAG with RAGAS Exercise 5: Creating a Ragas evaluation Exercise 6: Evaluating context retrieval with Ragas Exercise 7: Memory graphs Exercise 8: Saving conversation memory in the graph Exercise 9: Extracting facts from conversation histories Exercise 10: Using extracted conversation facts Exercise 11: Congratulations!