具有自动纠错能力的文本转 SQL 智能体

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具有自动纠错能力的文本转 SQL 智能体

作者:Aymeric Roucher

本教程演示如何使用 smolagents 实现一个能够运用 SQL 的智能体。

与标准的文本转 SQL 流水线相比,有什么优势?

标准的文本转 SQL 流水线比较脆弱,因为生成的 SQL 查询可能不正确。更糟的是,查询即使错误,也可能不会抛出异常,而是在没有警告的情况下给出错误或没有价值的结果。

👉 智能体系统能够审视输出,并判断是否需要修改查询,因此可显著改善表现。

下面来构建这个智能体!💪

建立 SQL 表

from sqlalchemy import (
    create_engine,
    MetaData,
    Table,
    Column,
    String,
    Integer,
    Float,
    insert,
    inspect,
    text,
)

engine = create_engine("sqlite:///:memory:")
metadata_obj = MetaData()

# create city SQL table
table_name = "receipts"
receipts = Table(
    table_name,
    metadata_obj,
    Column("receipt_id", Integer, primary_key=True),
    Column("customer_name", String(16), primary_key=True),
    Column("price", Float),
    Column("tip", Float),
)
metadata_obj.create_all(engine)

rows = [
    {"receipt_id": 1, "customer_name": "Alan Payne", "price": 12.06, "tip": 1.20},
    {"receipt_id": 2, "customer_name": "Alex Mason", "price": 23.86, "tip": 0.24},
    {"receipt_id": 3, "customer_name": "Woodrow Wilson", "price": 53.43, "tip": 5.43},
    {"receipt_id": 4, "customer_name": "Margaret James", "price": 21.11, "tip": 1.00},
]
for row in rows:
    stmt = insert(receipts).values(**row)
    with engine.begin() as connection:
        cursor = connection.execute(stmt)

先通过一个基本查询,检查系统是否正常工作:

>>> with engine.connect() as con:
...     rows = con.execute(text("""SELECT * from receipts"""))
...     for row in rows:
...         print(row)

(1, 'Alan Payne', 12.06, 1.2)
(2, 'Alex Mason', 23.86, 0.24)
(3, 'Woodrow Wilson', 53.43, 5.43)
(4, 'Margaret James', 21.11, 1.0)

构建智能体

现在通过一个工具,使 SQL 表可以被查询。

sql_engine 工具需要以下内容(更多细节请阅读 文档):

  • 包含 Args: 部分的文档字符串。它会被解析为工具的 description 属性,充当驱动智能体的 LLM 所使用的说明书,因此必须提供。

  • 输入和输出的类型提示。

from smolagents import tool


@tool
def sql_engine(query: str) -> str:
    """
    Allows you to perform SQL queries on the table. Returns a string representation of the result.
    The table is named 'receipts'. Its description is as follows:
        Columns:
        - receipt_id: INTEGER
        - customer_name: VARCHAR(16)
        - price: FLOAT
        - tip: FLOAT

    Args:
        query: The query to perform. This should be correct SQL.
    """
    output = ""
    with engine.connect() as con:
        rows = con.execute(text(query))
        for row in rows:
            output += "\n" + str(row)
    return output

接着创建一个使用该工具的智能体。

这里使用 CodeAgent,原文将其称为 transformers.agents 的主要智能体类:它以代码编写动作,并可依据 ReAct 框架根据先前输出继续迭代。

llm_engine 是驱动智能体系统的 LLM。InferenceClientModel 支持通过 Hugging Face Inference API 调用 LLM,可使用无服务器或专用端点;也可以使用任何专有 API,适配方式请参阅 另一篇实战教程。

from smolagents import CodeAgent, InferenceClientModel

agent = CodeAgent(
    tools=[sql_engine],
    model=InferenceClientModel("meta-llama/Meta-Llama-3-8B-Instruct"),
)

agent.run("Can you give me the name of the client who got the most expensive receipt?")

提高难度:表连接

现在提高难度:让智能体处理多张表之间的连接。

建立第二张表,记录各个 receipt_id 对应的服务员姓名!

table_name = "waiters"
receipts = Table(
    table_name,
    metadata_obj,
    Column("receipt_id", Integer, primary_key=True),
    Column("waiter_name", String(16), primary_key=True),
)
metadata_obj.create_all(engine)

rows = [
    {"receipt_id": 1, "waiter_name": "Corey Johnson"},
    {"receipt_id": 2, "waiter_name": "Michael Watts"},
    {"receipt_id": 3, "waiter_name": "Michael Watts"},
    {"receipt_id": 4, "waiter_name": "Margaret James"},
]
for row in rows:
    stmt = insert(receipts).values(**row)
    with engine.begin() as connection:
        cursor = connection.execute(stmt)

需要用这张表的说明更新 SQLExecutorTool,让 LLM 正确使用表中的信息。

>>> updated_description = """Allows you to perform SQL queries on the table. Beware that this tool's output is a string representation of the execution output.
... It can use the following tables:"""

>>> inspector = inspect(engine)
>>> for table in ["receipts", "waiters"]:
...     columns_info = [(col["name"], col["type"]) for col in inspector.get_columns(table)]

...     table_description = f"Table '{table}':\n"

...     table_description += "Columns:\n" + "\n".join([f"  - {name}: {col_type}" for name, col_type in columns_info])
...     updated_description += "\n\n" + table_description

>>> print(updated_description)

Allows you to perform SQL queries on the table. Beware that this tool's output is a string representation of the execution output.
It can use the following tables:

Table 'receipts':
Columns:
  - receipt_id: INTEGER
  - customer_name: VARCHAR(16)
  - price: FLOAT
  - tip: FLOAT

Table 'waiters':
Columns:
  - receipt_id: INTEGER
  - waiter_name: VARCHAR(16)

由于这个请求比前一个更难,接下来将 LLM 引擎切换为更强的 Qwen/Qwen2.5-72B-Instruct!

sql_engine.description = updated_description

agent = CodeAgent(
    tools=[sql_engine],
    model=InferenceClientModel("Qwen/Qwen2.5-72B-Instruct"),
)

agent.run("Which waiter got more total money from tips?")

原文展示的这个查询直接成功了。配置过程相当简单,对吧?

✅ 现在可以构建你一直想实现的文本转 SQL 系统了!✨

在 GitHub 更新

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