SWINGONE

包：classes12.jar,dom4j-1.6.1.jar,jxl.jar
创建sql语句
create table t_dep(
did number(5) primary key,
depname varchar2(15),
d_del number(5))

create table t_relation(
rid number(5) primary key ,
did number(5),skill varchar2(15),
d_del number(5))

create table t_staff(
snum number(15) primary key,
sname varchar2(15),
ssex char(2) default '男' constraint ssex_ck check(ssex in ('男','女')),
rid number(5),
spersonid varchar(20),
remarks varchar2(50),
d_del number(5)
);

alter table t_relation
add constraint d_fk foreign key(did) references t_dep(did);

alter table t_staff
add constraint s_fk foreign key(rid) references t_relation(rid);

create table t_user
(userid   number(5),
 username varchar2(15),
 pasword  varchar2(15)
)

insert into t_user values(1,'chinasoft','123456')

select * from
t_dep,t_relation,t_staff
where
t_dep.did = t_relation.did
and
t_relation.rid = t_staff.rid
and t_dep.did = 1;

DAO包
package dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import util.DBUtil;
public class ModifyPwd
{
    DBUtil db=new DBUtil(); 
    /*
     * 修改密码 
     * 参数1：新密码
     * 参数2：用户名
     * */
    public void modifyPwd(String pwd,String userName)
    {
     String sql="update t_user set pasword=? where username=?";
     Connection conn =null;
     PreparedStatement ps =null;
 
     try
     {
      conn =db.getConn();
      ps=conn.prepareStatement(sql);
   ps.setString(1, pwd);
   ps.setString(2, userName);
   ps.executeUpdate();
  }
     catch (SQLException e)
     {
   e.printStackTrace();
  }
     finally
     {
      try
      {
    ps.close();
    conn.close();
   }
      catch (SQLException e)
      {
    e.printStackTrace();
   }
      
     }
     
    }