我现在需要设计个毕业资料管理系统的后端，数据库里有学生，老师，毕业设计课题，我已经在mysql里添加了表格，接下来要设计计数据库对外接口，对外接口能写vscode里或者idea里吗，又该怎么写，请写一下具体代码

可以使用Java开发后端，以Spring Boot框架为例，设计一个Restful API对外提供接口。

首先，需要在maven中导入相关依赖：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
</dependencies>

然后，创建实体类，用于对应数据库表：

@Entity
@Table(name = "student")
public class Student {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private Integer age;
    // getters and setters
}

@Entity
@Table(name = "teacher")
public class Teacher {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private Integer age;
    // getters and setters
}

@Entity
@Table(name = "graduation_design")
public class GraduationDesign {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String title;
    private String description;
    private Long teacherId;
    // getters and setters
}

接着，创建对应的Repository类，用于操作数据库：

@Repository
public interface StudentRepository extends JpaRepository<Student, Long> {
}

@Repository
public interface TeacherRepository extends JpaRepository<Teacher, Long> {
}

@Repository
public interface GraduationDesignRepository extends JpaRepository<GraduationDesign, Long> {
    List<GraduationDesign> findByTeacherId(Long teacherId);
}

然后，创建对应的Controller类，用于处理请求：

@RestController
@RequestMapping("/api")
public class GraduationDesignController {
    @Autowired
    private StudentRepository studentRepository;
    @Autowired
    private TeacherRepository teacherRepository;
    @Autowired
    private GraduationDesignRepository graduationDesignRepository;

    @GetMapping("/students")
    public List<Student> getAllStudents() {
        return studentRepository.findAll();
    }

    @GetMapping("/teachers")
    public List<Teacher> getAllTeachers() {
        return teacherRepository.findAll();
    }

    @GetMapping("/graduation-designs")
    public List<GraduationDesign> getAllGraduationDesigns() {
        return graduationDesignRepository.findAll();
    }

    @GetMapping("/teachers/{teacherId}/graduation-designs")
    public List<GraduationDesign> getGraduationDesignsByTeacherId(@PathVariable Long teacherId) {
        return graduationDesignRepository.findByTeacherId(teacherId);
    }
}

最后，启动Spring Boot应用程序，就可以通过访问对应的接口来操作数据库了。比如：

- GET /api/students：获取所有学生信息
- GET /api/teachers：获取所有老师信息
- GET /api/graduation-designs：获取所有毕业设计信息
- GET /api/teachers/{teacherId}/graduation-designs：获取某个老师的所有毕业设计信息

可以使用VSCode或者IntelliJ IDEA等开发工具来编写代码。