Summary of PHP interview questions (with answers)

Recommended study "2019 PHP Interview Questions Summary (Collection)"

1. What is the difference between the get and post submission methods in the form?

Answer: get is to send a request through HTTP protocol and receive it through url parameter transmission, while post is entity data, and a large amount of information can be submitted through the form.

2.session and What is the difference between cookies?

Answer:

session: Stores the global unique variable accessed by the user, stored in the directory specified by PHP on the server (session_dir ) is stored in the location

cookie: Used to store when continuously accessing a page. It is stored on the client. For cookies, it is stored in the Temp directory of the user's WIN. of.

Both can set the length of time through time

3. What is the transaction in the database?

Answer: Transaction is An ordered set of database operations as a unit. A transaction is considered successful if all operations in the group succeed, even if only one operation fails, the transaction is not successful. If all operations are completed, the transaction is committed and its modifications are applied to all other database processes. If an operation fails, the transaction is rolled back and the effects of all operations in the transaction are canceled.

Brief question:

1. Use PHP to print out the time of the previous day in the format of 2006-5-10 22:21:21 (2 points) ****************

Answer: echo date('Y-m-d H:i:s', strtotime('-1 days'));

2. The difference between echo(), print(), and print_r() (3 points)

Answer:

echo and print are language structures , print_r is a function, the statement has no return value, the function can have a return value (even if it is useless)

print() can only print out the value of simple type variables (such as int, string)

print_r() can print out the value of complex type variables (such as arrays, objects)

echo Output one or more strings

3. Can use HTML and PHP separately Template (1 point)

Answer: Smarty, Dwoo, TinyButStrong, Template Lite, Savant, phemplate, XTemplate

4. What tools are used for version control? ( 1 point)

Answer: cvs, svn, vss;

5. How to achieve string flipping? (3 points)

Answer: echo strrev($a);

6. Methods to optimize MYSQL database. (4 points, the more you write, the more you get)

Answer:

1. Select the most applicable field attributes, reduce the length of the defined field as much as possible, and try to set the field to NOT NULL, for example 'Province, gender', it is best to set it to ENUM

2. Use JOIN to replace the subquery:

3. Use UNION to replace the manually created temporary table

4. Transaction processing:

5. Lock the table and optimize transaction processing:

6. Use foreign keys to optimize the locking table

7. Create index :

8. Optimize query statements

7. The meaning of PHP (send 1 point)

Answer: PHP is a server-based Scripting language for dynamic websites, you can use PHP and HTML to generate website homepage

8. What is the function of MYSQL to obtain the current time?, and the function of formatting date is (2 points)

Answer: now(), date()

9. A method to intercept Chinese strings without garbled characters. (3 points)******************

Mb_substr

Answer:

function GBsubstr($string, $start, $length) {
    if(strlen($string)>$length){
     $str=null;
     $len=$start+$length;
     for($i=$start;$i<$len;$i++){
    if(ord(substr($string,$i,1))>0xa0){
     $str.=substr($string,$i,2);
     $i++;
    }else{
     $str.=substr($string,$i,1);
     }
    }
   return $str.&#39;...&#39;;
    }else{
   return $string;
   }
}

10. Have you ever used version control software? If so, what is the name of the version control software you used? (1 point)

Answer: Used, cvs, svn, vss

11. Have you ever used a template engine? If so, what is the name of the template engine you used? (1 point)

Answer: Yes, smarty

12. Please briefly describe your most proud development work (4 points)

Answer: Information classification

13. What kind of methods do you use for large-traffic websites? How to solve the traffic problem? (4 points)

Answer:

Confirm whether the server hardware is enough to support the current traffic, separate database reading and writing, and optimize the data table,

Program function rules, prohibit external hot links, control the download of large files, use different hosts to divert main traffic

14. Use PHP to write the code to display the client IP and server IP 1 point)

Answer: Print client IP:

echo $_SERVER[‘REMOTE_ADDR’];
// 或者: 
getenv('REMOTE_ADDR');
// 打印服务器IP:
echo gethostbyname("www.bolaiwu.com")

15. What is the difference between the include and require statements? To avoid including the same file multiple times, you can use ( ?) statement to replace them? (2 points)

Answer: require->require is an unconditional inclusion, that is, if require is added to a process, require

will be executed first regardless of whether the condition is true or not.

include->include has a return value, but require does not (maybe because require is faster than include)

Note: require is fatal when the included file does not exist or has a syntax error, but include is not.

16. 在PHP中error_reporting这个函数有什么作用? (1分)

答:设置错误级别与错误信息回报

17. 请写一个函数验证电子邮件的格式是否正确 (2分)

答：

function checkEmail($email)
{
    $pregEmail = "/([a-z0-9]*[-_\.]?[a-z0-9]+)*@([a-z0-9]*[-_]?[a-z0-9]+)+[\.][a-z]{2,3}([\.][a-z]{2})?/i";
    return preg_match($pregEmail,$email);  
}

18. 简述如何得到当前执行脚本路径，包括所得到参数。(2分)

答:

$script_name = basename(__file__); 
print_r($script_name);

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