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安全地公开 SQL 查询

在不引入注入风险的情况下提供数据库读取访问。

安全地公开 SQL 查询 是 CoddyKit 上的免费 MCP Academy 课时。这是第 1 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 MCP Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 MCP Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Databases Behind a Tool

An MCP server can give a model real data by wrapping a database behind a tool, so the AI asks questions instead of touching raw tables. 🗄️

Reads, Not Writes

For safety, start by exposing only read access. Let the model query and report, but keep inserts, updates, and deletes off the table.

The Injection Danger

Never paste model text straight into SQL. That invites SQL injection, where crafted input rewrites your query and leaks or destroys data.

query = "SELECT * FROM users WHERE id = " + user_input  # unsafe!

Use Parameterized Queries

The fix is parameterized queries: you write placeholders and the driver binds values safely, so input can never change the query shape.

cur.execute("SELECT * FROM users WHERE id = ?", (user_id,))

Take Values as Arguments

Let the model pass values as typed arguments, then you build the query. The model supplies data, never the SQL text itself.

@mcp.tool()
def find_user(user_id: int) -> str:
    ...

Pin the Query Shape

Keep the SQL fixed in your code and only slot in bound parameters. A locked query shape is the simplest way to stay safe.

Use a Read-Only Role

Defense in depth: connect with a database read-only user. Even a buggy tool then physically cannot modify or drop your data.

Bound the Result Size

Always cap rows with a LIMIT so one broad query cannot dump a huge table into the model and blow your token budget.

cur.execute("SELECT name FROM users LIMIT 50")

Whitelist Allowed Tables

If the model picks a table, validate it against an allowlist. Reject anything not on the list instead of trusting the name.

Return Tidy Rows

Format results as clean text or simple records so the model reads them easily. Clarity in, clarity out for the next reasoning step.

Hide Sensitive Columns

Select only the columns the task needs. Leaving out secrets like password hashes keeps private data out of the model entirely.

Quick Check

What protects a SQL tool from injection?

Recap: Safe SQL

You exposed a database safely: parameterized read-only queries, allowlisted tables, and row limits. Next, wrap a web API. 🎯

常见问题解答

「安全地公开 SQL 查询」课时是免费的吗？

是的 — 「安全地公开 SQL 查询」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 MCP Academy 课程的其余内容，请升级到 CoddyKit PRO。 MCP Academy 课程共包含 4 节课。

「安全地公开 SQL 查询」这节课中我会学到什么？

在不引入注入风险的情况下提供数据库读取访问。你通过在浏览器中直接运行的动手代码来练习 MCP Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 MCP Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 MCP Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 1 节课，共 4 节。

「安全地公开 SQL 查询」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 MCP Academy 课中编写并运行代码吗？

能。每节 MCP Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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