問題描述

我正在將我的一些代碼從舊的 mysql 擴展轉換為 PHP 中的 mysqli 擴展.以前，使用mysql擴展，我曾使用過這樣的代碼來查找表中的主鍵:

I am converting some of my code from the older mysql extension to the mysqli extension in PHP. Previously, with the mysql extension, I had used some code like this to find the primary key in a table:

while ($i < mysql_num_fields($result)) {
    $meta = mysql_fetch_field($result, $i);
    if ($meta->primary_key == 1){ 
        $primary_key = $meta->name; 
    }
    $i++;
}

$meta->primary_key == 1 非常方便.

到目前為止，我已經轉換為使用 mysqli 的代碼:

So far I have converted to code to using mysqli:

while ($i < $result->field_count) {
    $meta = $result->fetch_field;
    if ($meta->primary_key == 1){ 
        $primary_key = $meta->name; 
    }
    $i++;
}

當然，通過查看文檔這里我們可以看到 $meta->primary_key 在 mysqli 中不存在.我看到有一個 $meta->flags.這是我最好的猜測，雖然我不確定當我有主鍵時 flags 應該是什么值.

Of course, from looking at the docs here we can see that $meta->primary_key doesn't exist in mysqli. I see that there is a $meta->flags. This is my best guess, although i am not sure of what value flags should be when I have a primary key.

有誰知道我如何使用 mysqli 判斷表的主鍵是哪一列?

Does anyone know how I tell which column is the primary key for a table using mysqli?

謝謝！

編輯這是一些工作代碼:

//get primary key
$primary_key = '';
while ($meta = $result->fetch_field()) {
    if ($meta->flags & MYSQLI_PRI_KEY_FLAG) { 
        $primary_key = $meta->name; 
    }
}

推薦答案

您已經非常接近了，您將需要 flags 屬性.

You were very close, you will need the flags property.

您正在尋找的標志是 MYSQLI_PRI_KEY_FLAG，意思是:

The flag you are looking for is MYSQLI_PRI_KEY_FLAG, which means:

字段是主索引的一部分

您可以使用以下內容測試此標志:

You can test for this flag with something like:

if ($meta->flags & MYSQLI_PRI_KEY_FLAG) { 
  //it is a primary key!
}

您在此處使用 & 作為 按位與運算符.

You are using & here as a Bitwise AND Operator.

這篇關于如何判斷列是否是使用 mysqli 的主鍵?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！