Question

我正在尝试对我构建的数据库运行查询，但我遇到了一个奇怪的问题当我运行查询（按名称）并提取结果。如果我在db中提取第一行，那么我可以使用其他参数运行另一个查询。如果我提取除第一行以外的行，则无法再访问我的数据库中的第一行

    Cursor cur =datasource.query( 2,new String[] {"_id","Player","Num_of_wrong_ans","Num_of_drunkness_checks"} , PlayerDatabaseHelper.PLAYER + " =? " ,new String[] {array[1]} , null ); 
            if(cur.moveToFirst())
            {                   
                id = cur.getString(cur.getColumnIndex(PlayerDatabaseHelper.ID));

            }
            cur.close();

查询方法是这样的：

    public Cursor query( int indicator,String[] projection, String selection,
        String[] selectionArgs, String sortOrder) {
    SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
    String a;
    switch (indicator) 
    { 
    case 1: 
        qb.setTables(PlayerDatabaseHelper.PLAYER_TABLE_NAME); 
        qb.setProjectionMap(projectionMap); 
        break; 
    case 2: 
        qb.setTables(PlayerDatabaseHelper.PLAYER_TABLE_NAME); 
        qb.setProjectionMap(projectionMap); 
        qb.appendWhere(PlayerDatabaseHelper.PLAYER);
        break; 
    default: 
        throw new IllegalArgumentException("Unknown  "); 
    } 

    // Get the database and run the query 
    SQLiteDatabase db = mHelper.getReadableDatabase(); 
    Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, null); 
    return c; 

}

我做错了什么???

在db中的第一个位置的sqlite中的查询

0 个答案: