android 提示这个错误 Caused by: android.database.sqlite.SQLiteException: no such column: xuehao:

这句话产生的     	Cursor cur=database.query(tablename, new String[]{XUEHAO,xingming}, null, null, null, null, null);

这个所有代码 public class Shu extends Activity {
	private static int          miCount         = 0;  
	private ListView list;
	private SQLiteDatabase database;
	private static String databasename="xuesheng.db";
	private static String tablename="table1";
	private static String XUEHAO="xuehao";
	private static String xingming="xingming";
	private static String createtable="CREATE TABLE "+tablename+"("+XUEHAO+" INTEGER PRIMARY KEY,"+xingming+"TEXT)";
 private Button add;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        list=(ListView)findViewById(R.id.listView1);
        add=(Button)findViewById(R.id.button1);
        database=this.openOrCreateDatabase(databasename, MODE_PRIVATE, null);
        try  
        {   
            /* 在数据库mSQLiteDatabase中创建一个表 */  
        	database.execSQL(createtable);   
        }   
        catch (Exception e)   
        {   
        	 audata();  
        }  
        add.setOnClickListener(new View.OnClickListener() {
    		
    		@Override
    		public void onClick(View v) {
    			// TODO Auto-generated method stub
    			 AddData();   
    		}
    	}) ;
    }
    public void AddData()   
    {   
        ContentValues cv = new ContentValues();   
        cv.put(XUEHAO, "111");   
        cv.put(xingming,  "sdaf");   
      
        /* 插入数据 */  
        database.insert(tablename, null, cv);   
        miCount++;   
        audata();   
    }   
    private void audata(){
    	
    	Cursor cur=database.query(tablename, new String[]{XUEHAO,xingming}, null, null, null, null, null);
    	
    	  miCount = cur.getCount();   
          if (cur != null && cur.getCount() >= 0)   
          {   
    	ListAdapter adapter=new SimpleCursorAdapter(this,
    			android.R.layout.易做图_list_item_2,
    			cur,
    			new String[]{XUEHAO,xingming},
    			new int[]{android.R.id.text1,android.R.id.text2});
    	
    	list.setAdapter(adapter);
    }
}}

追问：我的意思是 这个错误是什么造成的 ， 提示是没有xuehao    课一我已经定义了啊我的意思是 这个错误是什么造成的 ， 提示是没有xuehao    课一我已经定义了啊