doue9730 2018-08-16 12:13 采纳率: 100%
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Laravel从数据库中查找数据,直到它为空或重试完成

in my web application i want to search in database and when that is null i should store new data, for checking this operation i'm using do while statement with another option to check and search from database with limit period as retry, like with this code:

$retry = 0;
do {
    $feed = $feeds[array_rand($feeds)];
    $history = InstagramActionsHistory::wherePk($feed->pk)->whereActionName('comment')->first();
    $retry++;
} while ($history == null || $retry >= 3);

in this code while when $history is null or $retry is bigger than or equals with 3 statement should be break, but it doesn't work correctly

instead of that this code work correctly:

$retry = 0;
do {
    $feed = $feeds[array_rand($feeds)];
    $history = InstagramActionsHistory::wherePk($feed->pk)->whereActionName('comment')->first();
    $retry++;
    if ($history == null || $retry >= 3) {
        break;
    }
} while (true);

it seems multi condition dont work in while statement

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2条回答 默认 最新

  • dtsc14683 2018-08-16 12:35
    关注

    You should use logical operator.

    http://php.net/manual/en/language.operators.logical.php

    Modified code

    <?php 
    $retry = 0;
    do {
            $feed = $feeds[array_rand($feeds)];
            $history = InstagramActionsHistory::wherePk($feed->pk)->whereActionName('comment')->first();
            $retry++;
    } while ($history && $retry >= 3);
    ?>
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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