Mybatis主键生成方式

@Test
    public void testadd() throws IOException {
    //1.创建SQLSessionFactory对象
        SqlSessionFactory sqlSessionFactory = getSessionFactory();
        //回去sqlsession ，相当于jdbc中的connection
        SqlSession session = sqlSessionFactory.openSession();
        try {
            EmployeeMapper mapper = session.getMapper(EmployeeMapper.class);
            Employee employee = new Employee(null,"小花","[email protected]",30000.00,1);
            mapper.addEmployee(employee);
            session.commit();
            System.out.println("这个对象为"+employee);
        } finally {
            session.close();
        }

这个对象为Employee [id=null, lastName=小花, [email protected], salary=30000.0, deptId=1]

一、支持自增ID的数据库 如：mysql、sqlServer

<insert id="addEmployee" parameterType="com.atgui.spring.mybatis.entities.Employee"
   useGeneratedKeys="true" keyProperty="id">
      insert into employees(last_name,email,salary,dept_id) values(#{lastName},#{email},#{salary},#{deptId})
  </insert>

加上这个  employee ID值就有了

这个对象为Employee [id=7, lastName=小花, [email protected], salary=30000.0, deptId=1]

不支持自增的数据库  如：oracle