android sqlite删除查询不起作用

Question

以下sqlite查询不会删除以零开头的ID.

Android Sqlite表结构

 String CREATE_TABLE_BUS = "CREATE TABLE " + TABLE_BUS + "("
                    + KEY_TID + " INTEGER PRIMARY KEY AUTOINCREMENT,"    
                    + KEY_BUS_NUM + " TEXT,"
                    + KEY_BUS_NAME + " TEXT,"
                    + KEY_FROM + " TEXT,"
                    + KEY_TO + " TEXT,"
                    + KEY_TYPE + " TEXT"
                    + ")";

            db.execSQL(CREATE_TABLE_BUS);

为了某些目的,我将BUS_NUM保留为文本而不是int.

这是我调用删除行的函数..

        public void Delete_Bus(String bus_num) {
            SQLiteDatabase db = this.getWritableDatabase();

            db.delete(TABLE_BUS, KEY_BUS_NUM+"="+bus_num , null);
              Log.e("deleting bus num", bus_num);

            db.close(); // Closing database connection
        }

当代码不以零开头时,此代码非常正常.

它适用于76555而不适用于09877.我的代码出错了

Answer 1

此代码生成的查询结束如下:

DELETE FROM BusTable WHERE BusNum = 012345

数据库会将其解释为数字,而不是字符串.

在SQL中,必须引用字符串:

DELETE FROM BusTable WHERE BusNum = '012345'

但是,您可以避免使用参数格式化字符串:

db.delete(TABLE_BUS, KEY_BUS_NUM + " = ?", new String[] { bus_num });

Answer 2

也许..

public void Delete_Bus(String bus_num)
{
    SQLiteDatabase db=this.getWritableDatabase();
    db.execSQL("DELETE FROM "+TABLE_BUS+" WHERE "+KEY_BUS_NUM+"='"+bus_num+"'");
    db.close();
}