Write down the problems encountered in php interviews here_PHP Tutorial

Code optimization

Copy code The code is as follows:

for($i=0;$i<8;$i++){
array_push($week,$arr);
}

Copy code The code is as follows:

for($i=0;$i<8;$i++){
$week[]=$arr[$i];
}
//This way there is no need to call the function The additional burden

The benefits and disadvantages of indexing
Benefits: When querying, the number of rows with a specific value will be located in the index list at one time, greatly reducing traversal Number of matching rows
Disadvantages: This table has to be queried no matter what, and there are a lot of duplicate values ​​in the fields. It is meaningless to add indexes.
There are relatively few records. Adding indexes will not bring about speed optimization but will waste storage space. , because the index requires storage space, and a fatal disadvantage is that for each execution of update|insert|delete, the index of the field must be recalculated and updated.

http://www.bkjia.com/PHPjc/323587.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/323587.htmlTechArticleCode optimization copy code The code is as follows: for($i=0;$i8;$i++){ array_push($ week,$arr); } Copy the code as follows: for($i=0;$i8;$i++){ $week[]=$arr[$i]; } //This way there is no need to call the function...