android报错真的不知道怎么回事

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mymail/com.example.mymail.FeedbackShow}: android.database.sqlite.SQLiteException: no such table: feedbacklist (code 1): , while compiling: SELECT _id, fcontent, fstar FROM feedbacklist ORDER BY _id。。

关键代码如下

 public DbHelper(Context context) {
 this(context,DATANAME, VERSION);
 // TODO Auto-generated constructor stub
 }
 @Override
 public void onCreate(SQLiteDatabase db) {
 // TODO Auto-generated method stub
 System.out.println("create a Database");
 db.execSQL("create table contantslist(_id INTEGER PRIMARY KEY AUTOINCREMENT,username varchar(20),address varchar(20))");
 db.execSQL("create table feedbacklist(_id INTEGER PRIMARY KEY AUTOINCREMENT,fcontent varchar(250),fstar float(10))");
 }
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub
     onCreate(db); 
}
、、、、、、、、


DbHelper dbh=new DbHelper(FeedbackShow.this);
 db=dbh.getReadableDatabase();
cursor=db.query("feedbacklist",new String[]{"_id","fcontent","fstar"},null, null, null, null,"_id");

运行游标之前还可以，加上游标语句之后就不行,不知道如何是好了