@NamedQuery(query = "Select e from Employee e where e.eid = :id",    name = "find employee by id")

import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.NamedQuery;import javax.persistence.Table;@Entity@Table@NamedQuery(query = "Select e from Employee e where e.eid = :id",    name = "find employee by id")public class Employee {   @Id   @GeneratedValue(strategy= GenerationType.AUTO)      private int eid;   private String ename;   private double salary;   private String deg;   public Employee(int eid, String ename, double salary, String deg)    {    super( );    this.eid = eid;    this.ename = ename;    this.salary = salary;    this.deg = deg;   }   public Employee( )    {    super();   }      public int getEid( )    {    return eid;   }   public void setEid(int eid)     {    this.eid = eid;   }      public String getEname( )    {    return ename;   }   public void setEname(String ename)    {    this.ename = ename;   }      public double getSalary( )    {    return salary;   }   public void setSalary(double salary)    {    this.salary = salary;   }      public String getDeg( )    {    return deg;   }   public void setDeg(String deg)    {    this.deg = deg;   }   @Override   public String toString() {    return "Employee [eid=" + eid + ", ename=" + ename + ", salary="            + salary + ", deg=" + deg + "]";   }}

实体类之间的关系如下：

@ManyToOne 关系