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  • PHP PDO fetch all prepared statement
    PHP PDO fetch all prepared statement
    Use the fetchAll() method of PDO to get all query results at once. Pay attention to parameter binding, error handling and return format selection. 1. Ensure that the SQL statement is correct and call execute() to perform preprocessing; 2. It is recommended to use PDO::FETCH_ASSOC mode to return the associative array of field name keys; 3. Turn on the exception mode to facilitate debugging problems; 4. Avoid the default PDO::FETCH_BOTH mode to save memory; 5. If necessary, use try-catch to catch the exception to confirm the cause of errors.
    PHP Tutorial . Backend Development 592 2025-07-11 02:43:51
  • How to pass a variable by value to a PHP function?
    How to pass a variable by value to a PHP function?
    In PHP, by default, the function passes variables by value, which means that the function receives a copy of the original variable value. 1. When you pass a variable to a function, the modification of the variable inside the function will not affect the original variable outside the function; 2. If you want to modify the original variable inside the function, you can achieve it by returning a new value and reassigning the value to the original variable after being called; 3. Although using global variables is feasible, it is usually not recommended because it will make the code difficult to maintain and debug; 4. PHP has internally optimized large data structures such as arrays or objects (such as copying on write), so the performance impact of value passing is usually very small. Therefore, when using value transfer, you need to pay attention to the above characteristics to ensure code accuracy and efficiency.
    PHP Tutorial . Backend Development 274 2025-07-11 02:34:11
  • How to count the number of active sessions in PHP?
    How to count the number of active sessions in PHP?
    In PHP, counting the number of active sessions can be achieved in three ways: one is to read the session file, scan the file starting with sess\_ in the specified directory, and judge whether it is counted as active based on the last modification time (such as within the last 30 minutes). The sample code can count the number of files that meet the conditions; the second is to use the database or cache to store the session status, update the last active time at the beginning of each session, and query the number of active sessions within the specified time; the third is to maintain the "online user" table, update the last active time during access, and implement statistics through timed cleaning and query. Different solutions are suitable for different scenarios, and file methods are available for simple purposes. It is recommended to use databases or cache mechanisms in large systems.
    PHP Tutorial . Backend Development 333 2025-07-11 02:27:31
  • Describe the Use of `cURL` or `Guzzle` for HTTP Requests in PHP
    Describe the Use of `cURL` or `Guzzle` for HTTP Requests in PHP
    In PHP, cURL is suitable for projects that require underlying control and lightweight scenarios, and Guzzle is suitable for projects that pursue development efficiency and maintainability. 1.cURL is a built-in extension for PHP, suitable for scenarios where simple requests and no additional dependencies are required, but the code is cumbersome and error handling is complex; 2. Guzzle is a modern PHP library with good packaging, rich functions, and supports PSR standards, which is easy to integrate into large applications or frameworks; 3. The selection basis is project complexity: use cURL for simple scripts, and choose Guzzle when complex systems or advanced functions are required.
    PHP Tutorial . Backend Development 665 2025-07-11 02:25:51
  • How can you use php to interact with external APIs?
    How can you use php to interact with external APIs?
    Interaction with external APIs using PHP can be achieved through tools such as cURL or Guzzle. 1. Use cURL to send HTTP requests, execute the request through curl_init, curl_setopt configuration parameters, curl_exec and get the response, and finally curl_close closes the session; 2. Set CURLOPT_POST to true when sending POST requests, and pass data through CURLOPT_POSTFIELDS, pay attention to setting the correct Content-Type header; 3. Check the JSON format validity and HTTP status code when processing responses, handle error information, and pay attention to the rate limit and authentication requirements of the API; 4. Consider using Gu
    PHP Tutorial . Backend Development 434 2025-07-11 02:25:31
  • What is the difference between htmlspecialchars and htmlentities in PHP
    What is the difference between htmlspecialchars and htmlentities in PHP
    htmlspecialchars only encodes a few key HTML special characters to prevent XSS attacks and is suitable for user input processing; htmlentities encodes characters of all available HTML entities, suitable for multilingual content. For example, htmlspecialchars will escape, ",' (requires ENT_QUOTES), &, and htmlentities will also encode, such as é in café as é. When selecting, if you need to be secure and non-ASCII encoding, use htmlspecialchars, and if you need to be compatible with old systems or multiple languages, use htmlentities, and always specify UTF-8
    PHP Tutorial . Backend Development 378 2025-07-11 02:18:41
  • PHP header location not working in if statement
    PHP header location not working in if statement
    The header jump failure may be caused by four key points. 1.header() must be called before any output, including spaces or echo. It is recommended to use ob_start() to buffer the output; 2. If condition may not be true, check whether the variable is initialized, whether the comparison method is correct, and whether there is a spelling error; 3. Exit or die must be added after the header, otherwise subsequent code execution will affect the jump effect; 4. Check whether there are multiple redirect conflicts to ensure that the jump logic is handled in a unified manner to avoid repeated sending of headers.
    PHP Tutorial . Backend Development 788 2025-07-11 02:12:21
  • what is the difference between php array_merge and the operator
    what is the difference between php array_merge and the operator
    The key difference between array_merge() and operators when merging arrays is the processing of keys and the overlay of values. 1.array_merge() will re-index the numeric keys and retain the string keys. The key value of the same name in the subsequent array will overwrite the previous ones; 2. The operator will retain all keys. When encountering key conflicts, the value of the left array is retained, and the value of the right array is ignored. Therefore, if you need to allow overrides and don't mind the number keys being rearranged, use array_merge(); if you need to keep the original key value and avoid overrides, use the operator.
    PHP Tutorial . Backend Development 240 2025-07-11 02:11:11
  • PHP convert snake_case to camelCase string
    PHP convert snake_case to camelCase string
    In PHP, you can use two methods to convert snake_case to camelCase: 1. Use str_replace and ucwords to first uppercase the first letter of the underscore, then remove the underscore, and finally use lcfirst to ensure lowercase; 2. Use preg_replace_callback regular expression to complete the conversion step by step, match the lowercase letters after the underscore and convert them to uppercase; In addition, if the input may be in all uppercase format, it is recommended to convert to lowercase first to ensure consistency. At the same time, pay attention to the underscore when processing strings containing numbers or other symbols, you should ensure that letters are after underscore.
    PHP Tutorial . Backend Development 440 2025-07-11 02:04:01
  • Why is my PHP redirect not working
    Why is my PHP redirect not working
    PHP redirection does not work usually result from the following reasons: 1. The header has been sent, such as spaces, HTML or include file output; 2. The header() is used incorrectly, such as syntax problems or lack of exit; 3. The logic is not triggered, such as conditional judgment errors; 4. Cache or server behavior interference. Solutions include avoiding early output, using header() correctly and adding exit, checking logical flow, clearing cache, or using tools to detect responses.
    PHP Tutorial . Backend Development 625 2025-07-11 02:02:20
  • Can you nest functions in PHP?
    Can you nest functions in PHP?
    PHP does not allow the default definition of named functions within functions, but can use anonymous functions to implement nested behavior. 1. Named functions cannot be defined directly, otherwise repeated calls to outer functions will lead to fatal errors in repeated declarations of functions; 2. Closures (anonymous functions) can be used to simulate nested functions, store anonymous functions through variables and call them inside the outer function; 3. Use the use keyword to pass external variables into the closure; 4. The main uses of nested functions include limiting the scope of auxiliary functions, avoiding contaminating the global namespace, and encapsulating complex logic; 5. Pay attention to potential problems that may be caused by dynamic definition of functions.
    PHP Tutorial . Backend Development 292 2025-07-11 01:58:41
  • PHP str_replace vs preg_replace
    PHP str_replace vs preg_replace
    str_replace is used for simple string replacement and preg_replace is used for regular expression replacement. 1.str_replace is suitable for fixed string replacement, with fast execution speed and supports batch array replacement; 2.preg_replace supports pattern matching, group replacement and modifiers, which is suitable for processing regular dynamic text, but has complex syntax and low efficiency. When selecting, str_replace is used to process the determination value first, and preg_replace is used to process regular content.
    PHP Tutorial . Backend Development 513 2025-07-11 01:56:40
  • Discuss common security vulnerabilities in php web applications and how to prevent them.
    Discuss common security vulnerabilities in php web applications and how to prevent them.
    Common security vulnerabilities in PHP applications include SQL injection, XSS, file upload vulnerabilities, and CSRF. 1. Preprocessing statements should be used to prevent SQL injection, avoid splicing SQL strings, and checksum filtering of inputs; 2. Prevent XSS from escaping content before output, setting appropriate HTTP headers, and not trusting any user input; 3. Prevent file upload vulnerabilities to check file types, rename files, and prohibit uploading directories from executing scripts; 4. Prevent CSRF should use one-time tokens, check Referer and Origin headers, and use POST requests for sensitive operations. Security awareness should be strengthened during development and the built-in mechanism of the framework should be used reasonably to improve security.
    PHP Tutorial . Backend Development 506 2025-07-11 01:53:31
  • PHP prepared statement with LIKE operator
    PHP prepared statement with LIKE operator
    When using PHP preprocessing statements combined with LIKE for fuzzy queries, you need to pay attention to the parameter binding method and wildcard use. 1. You cannot directly write %'?%' in SQL because the question mark will be regarded as part of the string. The correct way is to pass % and search terms as parameters together or splice them on the PHP side before passing them in; 2. Multiple LIKE conditions can construct wildcard strings and bind parameters in turn, such as the fuzzy match between $searchName and $searchEmail corresponding to name and email; 3. Pay attention to the impact of input filtering, case sensitivity issues and full fuzzy query on performance to ensure that the code is safe and efficient.
    PHP Tutorial . Backend Development 905 2025-07-11 01:52:11

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