mirror of
https://github.com/hwchase17/langchain
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109 lines
3.5 KiB
Plaintext
109 lines
3.5 KiB
Plaintext
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# CnosDB
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> [CnosDB](https://github.com/cnosdb/cnosdb) is an open source distributed time series database with high performance, high compression rate and high ease of use.
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## Installation and Setup
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```python
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pip install cnos-connector
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```
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## Connecting to CnosDB
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You can connect to CnosDB using the SQLDatabase.from_cnosdb() method.
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### Syntax
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```python
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def SQLDatabase.from_cnosdb(url: str = "127.0.0.1:8902",
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user: str = "root",
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password: str = "",
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tenant: str = "cnosdb",
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database: str = "public")
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```
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Args:
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1. url (str): The HTTP connection host name and port number of the CnosDB
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service, excluding "http://" or "https://", with a default value
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of "127.0.0.1:8902".
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2. user (str): The username used to connect to the CnosDB service, with a
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default value of "root".
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3. password (str): The password of the user connecting to the CnosDB service,
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with a default value of "".
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4. tenant (str): The name of the tenant used to connect to the CnosDB service,
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with a default value of "cnosdb".
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5. database (str): The name of the database in the CnosDB tenant.
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## Examples
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```python
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# Connecting to CnosDB with SQLDatabase Wrapper
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from cnosdb_connector import make_cnosdb_langchain_uri
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from langchain import SQLDatabase
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db = SQLDatabase.from_cnosdb()
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```
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```python
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# Creating a OpenAI Chat LLM Wrapper
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from langchain.chat_models import ChatOpenAI
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llm = ChatOpenAI(temperature=0, model_name="gpt-3.5-turbo")
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```
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### SQL Chain
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This example demonstrates the use of the SQL Chain for answering a question over a CnosDB.
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```python
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from langchain import SQLDatabaseChain
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db_chain = SQLDatabaseChain.from_llm(llm, db, verbose=True)
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db_chain.run(
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"What is the average fa of test table that time between November 3,2022 and November 4, 2022?"
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)
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```
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```shell
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> Entering new chain...
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What is the average fa of test table that time between November 3, 2022 and November 4, 2022?
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SQLQuery:SELECT AVG(fa) FROM test WHERE time >= '2022-11-03' AND time < '2022-11-04'
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SQLResult: [(2.0,)]
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Answer:The average fa of the test table between November 3, 2022, and November 4, 2022, is 2.0.
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> Finished chain.
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```
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### SQL Database Agent
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This example demonstrates the use of the SQL Database Agent for answering questions over a CnosDB.
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```python
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from langchain.agents import create_sql_agent
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from langchain.agents.agent_toolkits import SQLDatabaseToolkit
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toolkit = SQLDatabaseToolkit(db=db, llm=llm)
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agent = create_sql_agent(llm=llm, toolkit=toolkit, verbose=True)
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```
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```python
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agent.run(
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"What is the average fa of test table that time between November 3, 2022 and November 4, 2022?"
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)
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```
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```shell
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> Entering new chain...
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Action: sql_db_list_tables
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Action Input: ""
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Observation: test
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Thought:The relevant table is "test". I should query the schema of this table to see the column names.
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Action: sql_db_schema
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Action Input: "test"
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Observation:
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CREATE TABLE test (
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time TIMESTAMP,
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fa BIGINT
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)
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/*
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3 rows from test table:
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fa time
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1 2022-11-03T06:20:11
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2 2022-11-03T06:20:11.000000001
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3 2022-11-03T06:20:11.000000002
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*/
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Thought:The relevant column is "fa" in the "test" table. I can now construct the query to calculate the average "fa" between the specified time range.
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Action: sql_db_query
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Action Input: "SELECT AVG(fa) FROM test WHERE time >= '2022-11-03' AND time < '2022-11-04'"
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Observation: [(2.0,)]
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Thought:The average "fa" of the "test" table between November 3, 2022 and November 4, 2022 is 2.0.
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Final Answer: 2.0
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> Finished chain.
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```
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