逻辑清理

Question

我目前有逻辑结构错误，我似乎想不出一种适当的方式写出来，所以它看起来很干净。目前，我的数据库中有一个名为USER的表。用户在众多字段中有6个字段，命名为：first、second、third、fourth、fifth、sixth。我的代码所做的就是用两个字段切换数据。因此，例如：first中的数据随着sixth中的数据而改变。

前：第一- 1，第六-6后，：第一- 6，第六-1

目前，我所拥有的是一些看起来非常混乱的东西，我不知道如何清理它。

if($switch == true){ /* $switch just indicates if the numbers being switched is one of the fields i.e. first, second, etc.. */
                if($slot == 1){ // The number is being switched into the first slot
                    if($first == $number){
                        return 1; // error, can't switch with itself
                    } else if ($second == $number){
                        $temp = $first;
                        // 1st QUERY TO UPDATE THE DATA IN FIRST, WITH THE DATA IN THE SECOND
                        // 2nd QUERY TO UPDATE THE DATA IN SECOND, WITH THE INFO STORED IN VARIABLE $temp
                    } else if ($third == $number){
                        $temp = $first;
                        // 1st QUERY TO UPDATE THE DATA IN FIRST, WITH THE DATA IN THE THIRD
                        // 2nd QUERY TO UPDATE THE DATA IN THIRD, WITH THE INFO STORED IN VARIABLE $temp 
                    } // ... continues to check for 4, 5, 6...
                } else if($slot == 2){ /* Then checks to see if it was slot 2, i.e. Second */
                    // ....
                } else if($slot == 3){ /* Then checks to see if it was slot 3, i.e. Third */
                    // ....
                } else if($slot == 4){ /* Then checks to see if it was slot 4, i.e. Fourth */
                    // ....
                } else if($slot == 5){ /* Then checks to see if it was slot 5, i.e. Fifth */
                    // ....
                } else if($slot == 6){ /* Then checks to see if it was slot 6, i.e. Sixth */
                    // ....
                }

}

每个时隙都会继续，每次6次.我知道编程很糟糕，但我刚刚开始学习PHP (这是我的第一种语言，所以请原谅我)。有什么建议可以让这个更干净吗？或者更好的写作方式？如果有人想通过Skype或其他方式向我解释，我会非常感激的。谢谢。

Answer 1

你可以这样做：

// This function returns the column name for the specified slot
function getSlotColumn($slotNum)
{
    switch($slotNum)
    {
        case 1:
            retrun "first";

        case 2:
            return "second";

        ......
    }
}

然后在开关函数中

// This function swaps the values of the two specified slots
function swapValues($slot1Num, $slot2Num)
{
    if($slot1Num == $slot2Num) return;
    if($slot1Num < 1 || $slot1Num > 6) return;
    if($slot2Num < 1 || $slot2Num > 6) return;

    $slot1Col = getSlotColumn($slot1Num);
    $slot2Col = getSlotColumn($slot2Num);

            //get value of the first slot
    $slot1Val = //SELECT $slot1Col FROM ... WHERE ... slot

    // Now since we have the value of the first slot, we can update it from the second slot with this pseudo query
    //UPDATE ... SET $slot1Col = $slot2Col WHERE ...

    // Then update second slot from the value in $slot1Val
    //UPDATE ... SET $slot2Col = $slot1Val WHERE ...
}

然后像这样使用它：

if(switch == true)
{
    swapValues(1, 6);
}

Answer 2

使用 statement

if($switch == true){ 
    switch($slot) {
        case 1 :
            if($first == $number){
                return 1; // error, can't switch with itself
            } else if ($second == $number){
                $temp = $first;
                // 1st QUERY TO UPDATE THE DATA IN FIRST, WITH THE DATA IN THE SECOND
                // 2nd QUERY TO UPDATE THE DATA IN SECOND, WITH THE INFO STORED IN VARIABLE $temp
            } else if ($third == $number){
                $temp = $first;
                // 1st QUERY TO UPDATE THE DATA IN FIRST, WITH THE DATA IN THE THIRD
                // 2nd QUERY TO UPDATE THE DATA IN THIRD, WITH THE INFO STORED IN VARIABLE $temp 
            } 
            break;
        case 2 :
            // ....
            break;
        case 3 :
            // ....
            break;
        case 4 :
            // ....
            break;
        case 5 :
            // ....
            break;
        case 6 :
            // ....
            break;
        default:
            // ...
    }    
}    

您会注意到底部有一个default。如果你的条件都不匹配的话，最好把它放在适当的位置。

还请注意break关键字。如果没有它，代码块不会在结束时停止，并将“通过”到下一个块。这有时很方便，但在你的情况下就不行了。