1. 引言
在现代数据处理场景中，用户通常希望通过自然语言与数据库交互，而无需编写复杂的SQL语句。这种需求推动了大模型在自然语言处理（NLP）和数据库查询生成领域的应用。本文将详细介绍如何使用大模型实现自然语言查询关系型数据库SQL的功能，包括技术原理、架构设计、代码实现以及参数配置。
2. 技术原理
大模型通过理解用户输入的自然语言问题，并将其转换为对应的SQL查询语句，从而实现对关系型数据库的查询操作。以下是该功能的核心原理：
- 自然语言理解：大模型首先需要解析用户输入的自然语言问题，提取其中的关键信息（如实体、关系、条件等）。SQL生成：基于解析后的语义信息，大模型生成符合数据库模式的SQL查询语句。执行与返回结果：生成的SQL语句被发送到数据库执行，并将查询结果返回给用户。
3. 架构设计
以下是大模型实现自然语言查询关系型数据库SQL的典型架构：
- 前端接口层：
提供RESTful API接口，接收用户输入的自然语言问题。
示例代码如下：
package com.alibaba.example.sql.controller;import java.io.IOException;import java.nio.charset.Charset;import java.util.List;import java.util.Map;import com.alibaba.example.sql.SQLGenerationException;import org.springframework.ai.chat.client.ChatClient;import org.springframework.beans.factory.annotation.Value;import org.springframework.core.io.Resource;import org.springframework.jdbc.core.JdbcTemplate;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class SQLController {@Value("classpath:/schema.sql")private Resource ddlResource;@Value("classpath:/sql-prompt-template.st")private Resource sqlPromptTemplateResource;private final ChatClient chatClient;private final JdbcTemplate jdbcTemplate;public SQLController(ChatClient.Builder aiClientBuilder,JdbcTemplate jdbcTemplate) {this.chatClient = aiClientBuilder.build();this.jdbcTemplate = jdbcTemplate;}@PostMapping(path = "/sql")public Answer sql(@RequestBody SqlRequest sqlRequest) throws IOException {String schema = ddlResource.getContentAsString(Charset.defaultCharset());String sqlPromptTemplate = sqlPromptTemplateResource.getContentAsString(Charset.defaultCharset());String query = chatClient.prompt().user(userSpec -> userSpec.text(sqlPromptTemplate).param("question", sqlRequest.question()).param("ddl", schema)).call().content();assert query != null;if (query.toLowerCase().startsWith("select")) {return new Answer(query,jdbcTemplate.queryForList(query));}throw new SQLGenerationException(query);}public record SqlRequest(String question) { }public record Answer(String sqlQuery, List<Map<String, Object>> results) { }}- 大模型服务层：
- 使用预训练的大模型（如DashScope）生成SQL查询。配置文件中需指定大模型的API密钥：
spring: ai: dashscope: api-key: ${AI_DASHSCOPE_API_KEY:sk-7074dss9idjddkkdbf31ssss}- 数据库层：
- 配置数据库连接信息，支持执行生成的SQL查询。示例配置如下：
spring: datasource: url: jdbc:mysql://IP:3306/DB?useSSL=false&serverTimezone=UTC username: test password: h4tewdwerwefgvfebU driver-class-name: com.mysql.cj.jdbc.Driver4. 参数配置与分析
以下是关键参数的配置规则及使用方法：
sql-prompt-template.st：
- 定义了SQL生成的模板，包含问题和数据库模式的占位符。示例模板：
Given the DDL in the DDL section, write an SQL query to answer the question in the QUESTION section.Only produce select queries. If the question would result in an insert, update,or delete, or if the query would alter the DDL in any way, say that the operationisn't supported. If the question can't be answered, say that the DDL doesn't supportanswering that question.Answer with the raw SQL query only; no markdown or other punctuation that isn't part of the query itself.QUESTION{question}DDL{ddl}schema.sql：
- 定义了数据库的表结构，供大模型参考生成SQL。示例表结构：
create table Authors ( id int not null auto_increment, firstName varchar(255) not null, lastName varchar(255) not null, primary key (id));create table Publishers ( id int not null auto_increment, name varchar(255) not null, primary key (id));create table Books ( id int not null auto_increment, isbn varchar(255) not null, title varchar(255) not null, author_ref int not null, publisher_ref int not null, description varchar(255) DEFAULT NULL, primary key (id));data.sql：- 初始化数据库中的测试数据。示例数据：
insert into Authors (firstName, lastName) values ('Craig', 'Walls');insert into Authors (firstName, lastName) values ('Josh', 'Long');insert into Authors (firstName, lastName) values ('Ken', 'Kousen');insert into Authors (firstName, lastName) values ('Venkat', 'Subramaniam');insert into Publishers (name) values ('Manning Publications');insert into Publishers (name) values ('OReilly Media');insert into Publishers (name) values ('Pragmatic Bookshelf');insert into Books (isbn, title, author_ref, publisher_ref)values ('9781617292545', 'Spring Boot in Action', 1, 1);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781617297571', 'Spring in Action', 1, 1);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781680507256', 'Build Talking Apps for Alexa', 1, 3);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781934356401', 'Modular Java', 1, 3);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781449374648', 'Cloud Native Java', 2, 2);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781680508222', 'Help Your Boss Help You', 3, 3);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781492046677', 'Kotlin Cookbook', 3, 2);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781680509816', 'Cruising Along with Java', 4, 3);insert into Books (isbn, title, author_ref, publisher_ref)values ('9781680506358', 'Programming Kotlin', 4, 3); 5. 测试验证
为了验证系统的正确性，可以设计以下测试用例：
测试用例1：
- 输入问题：
"Find all books written by Craig Walls."预期SQL：SELECT * FROM Books WHERE author_ref = (SELECT id FROM Authors WHERE firstName = 'Craig' AND lastName = 'Walls');预期结果：返回所有由Craig Walls撰写的书籍。测试用例2：
- 输入问题：
"Insert a new author into the Authors table."预期响应："Operation not supported."测试用例3：
- 输入问题：
"What is the total number of books published by each publisher?"预期SQL：SELECT p.name, COUNT(*) AS book_count FROM Books b JOIN Publishers p ON b.publisher_ref = p.id GROUP BY p.name;预期结果：返回每个出版社出版的书籍总数。