Problems using thinkphp and php-preg_replace, chain query

This article talks about the problems encountered when using thinkphp:

1. About chain query

$post_db = D('Post');

$total=

$

total

->where($where1);;$list=$total->order($order)->limit($limit)->select();

$count=$total-> ;count();At this time we discovered that the value of $count is not the quantity we found, but the total amount, and the expression$total=$

total->where($where1); has the same effect as$

total->where($where1);, the value of $total will change. If we When you need to query the total number, you can only query it again. This is a very inhumane function in thinkphp;

2. PHP’s native function: preg_replace()

Requirement: I want to modify a specific value in the text through preg_replace()The initial use is as follows: (When backing up SQL, modify the starting value of the auto-increment. Why is there such a need? This involves backing up the log file and backing up in batches when backing up the database. At this time, the log has been increasing, resulting in the auto-increment value. Mismatch, there is a problem when restoring data)Preg_replace('/AUTO_INCREMENT=(d+)/', 'AUTO_INCREMENT='."$1" + 2, $sql);We found that it will be replaced with AUTO_INCREMENT= 2 And $ 1 is not recognized,and use 'auto_increment ='. "$ 1" can be identified alone. There will be problems with the use of variables. I didn’t check the specific reasons.My solution is:if(preg_match('/AUTO_INCREMENT=(d+)/',$sql,$matches) ){

place('/AUTO_INCREMENT=(d+)/', 'AUTO_INCREMENT= '.$auto_int_start, $sql);

That is, calculate it in advance and then replace it. Let’s look at the specific reason later. If any students know the principle, you can also leave a message to tell me, 3Q!

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The above introduces the problems in using thinkphp and php - preg_replace, chain query, including the content. I hope it will be helpful to friends who are interested in PHP tutorials.