对表的增删改查.doc

如：A表中有 a1,b1,c1,a2 四个字段，B表中有b1,b2，两个字段，C表中有c1,c2两个字段,a1,b1,c1分别为 A,B,C表的主键，现要对A表进行增、删、改，sql语句写法？本人设计时考虑时，遇到的第一个问题：a1为A的ID，a2为其名字，b1、c1为B、C的ID，b2,c2为名字，界面设计时把b1，c1字段都设计为下拉框，但现在我遇到的表B中字段特别多，如果都设计为下拉框，半个屏幕都成了下拉框，以及后台操作用的sql语句也不知道怎么写？会者帮忙，谢谢！ 对我有用0丢个板砖0引用举报管理TOP 回复次数：11 bea_java(灰常)等级：#1楼 得分：10回复于：2009-08-09 23:41:36如果你用了hibernate就设置级联删除如果没有用hibernate 就需要 写n条sql语句了，先删除子表，然后删除主表内容，不过这个要注意使用事务去处理。对我有用0丢个板砖0引用举报管理TOP精华推荐：【投票】对于达到一定结贴率的楼主【不】在使用【机器人】提示其结贴信息。现征求大家的意见 bea_java(灰常)等级：#1楼 得分：10回复于：2009-08-09 23:41:36如果你用了hibernate就设置级联删除如果没有用hibernate 就需要 写n条sql语句了，先删除子表，然后删除主表内容，不过这个要注意使用事务去处理。对我有用0丢个板砖0引用举报管理TOP精华推荐：【投票】对于达到一定结贴率的楼主【不】在使用【机器人】提示其结贴信息。现征求大家的意见zl3450341(东走西顾)等级：2#2楼 得分：0回复于：2009-08-09 23:56:24beanJava codepackage org.bean;public class FligthInfo private int flightId; private String fligthNo; private String fligthTime; private String fligthPrice; private int corporationId; /B表字段 private String corporationName; /B表字段 public int getFlightId() return flightId; public void setFlightId(int flightId) this.flightId = flightId; public String getFligthNo() return fligthNo; public void setFligthNo(String fligthNo) this.fligthNo = fligthNo; public String getFligthTime() return fligthTime; public void setFligthTime(String fligthTime) this.fligthTime = fligthTime; public String getFligthPrice() return fligthPrice; public void setFligthPrice(String fligthPrice) this.fligthPrice = fligthPrice; public int getCorporationId() return corporationId; public void setCorporationId(int corporationId) this.corporationId = corporationId; public String getCorporationName() return corporationName; public void setCorporationName(String corporationName) this.corporationName = corporationName; DAOJava codepackage org.dao;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.ArrayList;import org.bean.FligthInfo;import org.util.ConDB;public class FligthDao /查 public ArrayList findAllFligth() ArrayList fligthList =new ArrayList(); Connection con=ConDB.getConnection(); String sql=select * from T_flight a,T_corporation b where a.corporation_Id=b.corporation_Id; System.out.println(sql); Statement stm=null; ResultSet rs=null; try stm=con.createStatement(); rs=stm.executeQuery(sql); while(rs.next() FligthInfo fligth=new FligthInfo(); fligth.setCorporationId(rs.getInt(corporation_Id); fligth.setCorporationName(rs.getString(corporation_name); fligth.setFlightId(rs.getInt(flight_Id); fligth.setFligthNo(rs.getString(flight_no); fligth.setFligthPrice(rs.getString(price); fligth.setFligthTime(rs.getString(flight_time); fligthList.add(fligth); catch (SQLException e) / TODO Auto-generated catch block e.printStackTrace(); finally ConDB.closeRs(rs); ConDB.closeStm(stm); ConDB.closeCon(con); return fligthList; /增 public int insertFligth(FligthInfo fligth) int flag=-1; Connection con=ConDB.getConnection(); String sql=insert into T_flight values(+fligth.getFligthNo()+,+fligth.getFligthTime()+,+fligth.getFligthPrice()+,+fligth.getCorporationId()+); System.out.println(sql); Statement stm=null; try stm=con.createStatement(); flag=stm.executeUpdate(sql); catch (SQLException e) / TODO Auto-generated catch block e.printStackTrace(); finally ConDB.closeStm(stm); ConDB.closeCon(con); return flag; servlet 添加数据Java codepackage org.service;import java.io.IOException;import java.io.PrintWriter;import java.util.ArrayList;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.bean.FligthInfo;import org.dao.FligthDao;public class InsertFligth extends HttpServlet /* * The doGet method of the servlet. * * This method is called when a form has its tag value method equals to get. * * param request the request send by the client to the server * param response the response send by the server to the client * throws ServletException if an error occurred * throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException FligthInfo fligth=new FligthInfo(); fligth.setFligthNo(request.getParameter(fligthNo); fligth.setFligthPrice(request.getParameter(fligthPrice); fligth.setCorporationId(Integer.parseInt(request.getParameter(corporationId); fligth.setFligthTime(request.getParameter(fligthTime); FligthDao fDao=new FligthDao(); fDao.insertFligth(fligth); request.getRequestDispatcher(/servlet/FindAllFligth).forward(request, response); /* * The doPost method of the servlet. * * This method is called when a form has its tag value method equals to post. * * param request the request send by the client to the server * param response the response send by the server