example

minimal-example.py

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+# This example does not use a langchain agent, 
+# The langchain sql chain has knowledge of the database, but doesn't interact with it becond intialization.
+# The output of the sql chain is parsed seperately and passed to `duckdb.sql()` by streamlit
+
+import streamlit as st
+
+## Database connection
+from sqlalchemy import create_engine
+from langchain.sql_database import SQLDatabase
+db_uri = "duckdb:///pad.duckdb"
+engine = create_engine(db_uri, connect_args={'read_only': True})
+db = SQLDatabase(engine, view_support=True)
+
+import duckdb
+
+con = duckdb.connect("pad.duckdb", read_only=True)
+con.install_extension("spatial")
+con.load_extension("spatial")
+
+## ChatGPT Connection
+from langchain_openai import ChatOpenAI 
+chatgpt_llm = ChatOpenAI(model="gpt-3.5-turbo", temperature=0, api_key=st.secrets["OPENAI_API_KEY"])
+chatgpt4_llm = ChatOpenAI(model="gpt-4", temperature=0, api_key=st.secrets["OPENAI_API_KEY"])
+
+
+# Requires ollama server running locally
+from langchain_community.llms import Ollama
+## # from langchain_community.llms import ChatOllama
+ollama_llm = Ollama(model="duckdb-nsql", temperature=0)
+
+models = {"ollama": ollama_llm, "chatgpt3.5": chatgpt_llm, "chatgpt4": chatgpt4_llm}
+with st.sidebar:
+    choice = st.radio("Select an LLM:", models)
+    llm = models[choice]
+
+## A SQL Chain
+from langchain.chains import create_sql_query_chain
+chain = create_sql_query_chain(llm, db)
+
+# agent does not work
+# agent = create_sql_agent(llm, db=db, verbose=True)
+
+if prompt := st.chat_input():
+    st.chat_message("user").write(prompt)
+    with st.chat_message("assistant"):
+        response = chain.invoke({"question": prompt})
+        st.write(response)
+
+        tbl = con.sql(response).to_df()
+        st.dataframe(tbl)
+
+
+# duckdb_sql fails but chatgpt3.5 succeeds with a query like:
+# use the st_area function and st_GeomFromWKB functions to compute the area of the Shape column in the fee table, and then use that to compute the total area under each GAP_Sts category
+
+
+# Federal agencies are identified as 'FED' in the Mang_Type column in the 'combined' data table. The Mang_Name column indicates the different agencies. Which federal agencies manage the greatest area of GAP_Sts 1 or 2 land?
+