学生课绩管理系统 (升级版)

				import java.sql.*;
				public class course {  
				  private String id;
				  private String name;
				  private String dep;
				  private String prepare;
				  private int mark;
				  
				  public void setPrepare(String s){prepare=s;}
				  public String getPrepare(){return prepare;}
				  public void setMark(int s){mark=s;}
				  public int getMark(){return mark;}
				  public void setDep(String s){dep=s;}
				  public String getDep(){return dep;}
				  public String getId() {
				    return id;
				  }
				  public void setId(String id) {
				    this.id = id;
				  }
				  public String getName() {
				    return name;
				  }
				  public void setName(String name) {
				    this.name = name;
				  }
				
				  public ResultSet getPrepares(){               //得到所能选择的预修课
				 	String sql="select name,id from course   ";
				 	sqlBean db = new sqlBean();
				 	ResultSet rs = db.executeQuery(sql);
				 	return rs; 	
				 	}
				 	
				 		
				 	public String getPrepareDep(){                 //察看预修课所在系
				 		String s="no";
				 	String sql="select dep from course where id='"+prepare+"' ";
				 	sqlBean db = new sqlBean();
				 	try{
				 	ResultSet rs = db.executeQuery(sql);
				 	if(rs.next()){
				 	   s=rs.getString("dep");  	   			
				 		}
				 	}catch(Exception e){ e.getMessage();}		
				 	return s;}
				 	
				 	
				    public ResultSet  getCourse(){         //察看所有课程
						String sql="select * from course   ";
						sqlBean db= new sqlBean();
						ResultSet rs = db.executeQuery(sql);
						 return rs;
						                         }
						                         
						                         
				    public int deleteCourse(String id){  
				        int num=0; 	
				    	String sql="delete  from Course where id ='"+id+"' ";
				    	sqlBean db= new sqlBean();
				        num=db.executeDelete(sql);
				        return num;
				    	}                                           	
				 	
				 	public String getPrepareDep(String id){
				 		String dep="";
				 		String sql="select dep from course where id='"+id+"'";
				 		sqlBean db= new sqlBean();
				 		try{
				 		ResultSet rs = db.executeQuery(sql);
				 		if(rs.next()) 
				 		dep=rs.getString("dep");
				 	       }catch(SQLException e){System.out.print(e.toString());}
				 		return dep;
				 		}
				    public void updateCourse(String id){    	
				      String sql="update course "+
				                 " set name='"+name+"',prepare='"+prepare+"',"+
				                 "dep='"+dep+"',mark='"+mark+"'  "+
				                 " where id='"+id+"' ";
				                 sqlBean db= new sqlBean();
				                 db.executeInsert(sql);
				                 }
				    	
				    	
				 	public void addCourse(){      
				 		String sql="insert into course(id,name,mark,prepare,dep) "+
				 		           "VALUES('"+id+"','"+name+"','"+mark+"','"+prepare+"','"+dep+"') ";
				 		 sqlBean db = new sqlBean();
				 		 db.executeInsert(sql);           
				 		                  }	
				 	
				    public boolean hasLogin( String id){
				    	boolean f=true;
				    	String sql="select id from course where id='"+id+"'  ";
				    	sqlBean db = new sqlBean();
				    	try{
				    	ResultSet rs =db.executeQuery(sql);
				    	if(rs.next())
				    	{f=false;}
				          }catch(Exception e){ e.getMessage();}
				    	return f;   
				    	}
				}