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  • Why use prepared statements in PHP
    Why use prepared statements in PHP
    Use prepared statements in PHP mainly to prevent SQL injection attacks, improve performance, make the code clearer and easier to debug. 1. It effectively prevents SQL injection through parameterized queries, ensuring that user input is always processed as data rather than SQL logic; 2. Preprocessing statements only need to be compiled once when executed multiple times, significantly improving execution efficiency, especially suitable for batch operations; 3. Parameter binding supports position and named placeholders, separates SQL and data, and enhances code readability and maintenance; 4. Errors can be exposed in advance in the prepare stage, and exceptions can be handled uniformly by setting error mode, which helps to quickly debug.
    PHP Tutorial . Backend Development 288 2025-07-13 01:52:51
  • How does php handle sessions and cookies?
    How does php handle sessions and cookies?
    PHPmanagessessionsandcookiestomaintainstateacrossHTTPrequests.1.Sessionsstoredataserver-side,usingauniquesessionIDstoredtypicallyinacookie(PHPSESSID).2.Cookiesstoredataclient-side,setviasetcookie()andaccessedthrough$_COOKIE.3.Sessionsaresaferforsensi
    PHP Tutorial . Backend Development 151 2025-07-13 01:50:11
  • What is polymorphism in php OOP and how is it achieved?
    What is polymorphism in php OOP and how is it achieved?
    PolymorphisminPHPOOPallowsdifferentclassestobetreatedasobjectsofacommonsuperclassorinterfacewhilemaintainingtheiruniquebehaviors.1.Itisachievedprimarilythroughmethodoverriding,whereasubclassredefinesamethodfromitsparentclass,enablingdistinctresponses
    PHP Tutorial . Backend Development 465 2025-07-13 01:40:01
  • how to escape special characters in php regex
    how to escape special characters in php regex
    The key to handling special characters in PHP regular expressions is to use backslashes for escape. 1. The purpose of escape is to allow the regular engine to treat special characters as ordinary characters to avoid matching failures or syntax errors; 2. Common characters that need to be escaped include ., ^, $, *, , ?, {,}, [,], (,), \, |, :, =,!, etc.; 3. You can use the preg_quote function to efficiently escape the entire string automatically, and pay attention to adding delimiters; 4. Indicating an actual backslash in the string, you need to write two backslashes to ensure that they are correctly passed to the regular engine; 5. When using it, it is recommended to use online tools to test and confirm the role of characters to improve accuracy and efficiency. Master these key points to correctly handle the special features in PHP regulations
    PHP Tutorial . Backend Development 413 2025-07-13 01:29:21
  • PHP substr_count usage
    PHP substr_count usage
    The substr_count function is used to count the number of occurrences of substrings. The syntax is substr_count($haystack,$needle), for example, counting the number of occurrences of "apple"; note points include: 1. Manual conversion and unified conversion are required for case sensitivity; 2. Overlapping matches are not handled, such as "aa" in "aaa" only counts twice; 3. The parameter order cannot be reversed; 4. Multi-byte characters need to be expanded by mbstring; application techniques such as combining str_replace to judge replacement, filter keyword frequency, and avoid misjudgment of empty strings.
    PHP Tutorial . Backend Development 811 2025-07-13 01:21:40
  • how to convert a string to a php array
    how to convert a string to a php array
    To convert a string to a PHP array, you need to select the method according to the format: 1. Use exploit() to separate the comma and use array_map(trim) to remove spaces; 2. Use json_decode($str,true) to parse; 3. Use parse_str() to convert the associative array to the URL parameters; 4. Complex structures combine functions such as preg_split() and exploit() to process key-value pairs. Different formats correspond to different conversion strategies, and the key is to identify the string structure.
    PHP Tutorial . Backend Development 297 2025-07-13 01:05:41
  • How to fix PHP header already sent error
    How to fix PHP header already sent error
    The error "Cannotmodifyheaderinformation-headersalreadysent" is because there is already output of content before trying to modify the header in PHP. 1. Check whether there are spaces or line breaks at the beginning of the PHP file to ensure that the label and the blank spaces after it are used; 4. Check whether the included files have introduced unexpected output, and you can use the ob_start() buffer to control the output.
    PHP Tutorial . Backend Development 301 2025-07-13 00:32:32
  • How do you securely connect to a database using php?
    How do you securely connect to a database using php?
    To securely connect to a database in PHP, several critical steps are required. First, use PDO to prevent SQL injection with preprocessing statements to ensure that SQL logic is separated from data; second, store database credentials in non-Web root directory or use environment variable management through .env files, and avoid submission to version control; third, enable SSL encrypted database connections to ensure that the latest certificate is held; finally, properly handle error information, record errors internally instead of showing detailed content to users, thereby avoiding the leakage of sensitive information. The above measures jointly ensure the security of database connections.
    PHP Tutorial . Backend Development 687 2025-07-13 00:30:20
  • What are Traits in php and when should you use them?
    What are Traits in php and when should you use them?
    TraitsinPHPareamechanismforcodereuseacrossclasseswithoutinheritance,allowingmethodstobesharedamongunrelatedclasses.Theyhelpavoidcodeduplicationbyenablingtheinclusionofmethodcollectionsdirectlyintoclasses.Traitsshouldbeusedwhenmultipleunrelatedclasses
    PHP Tutorial . Backend Development 380 2025-07-13 00:21:10
  • How does php implement namespaces and autoloading with Composer?
    How does php implement namespaces and autoloading with Composer?
    PHPusesnamespacestoorganizecodeandavoidnamingconflictsbygroupingrelatedclassesunderlogicalprefixes,forexampledefiningaclassintheApp\UtilitiesnamespacewithnamespaceApp\Utilities;.ComposerenhancesthisbyimplementingautoloadingthroughconfigurationslikePS
    PHP Tutorial . Backend Development 649 2025-07-12 03:16:01
  • How to access a character in a string by index in PHP
    How to access a character in a string by index in PHP
    In PHP, you can use square brackets or curly braces to obtain string specific index characters, but square brackets are recommended; the index starts from 0, and the access outside the range returns a null value and cannot be assigned a value; mb_substr is required to handle multi-byte characters. For example: $str="hello";echo$str[0]; output h; and Chinese characters such as mb_substr($str,1,1) need to obtain the correct result; in actual applications, the length of the string should be checked before looping, dynamic strings need to be verified for validity, and multilingual projects recommend using multi-byte security functions uniformly.
    PHP Tutorial . Backend Development 813 2025-07-12 03:15:40
  • PHP prepared statement SELECT
    PHP prepared statement SELECT
    Execution of SELECT queries using PHP's preprocessing statements can effectively prevent SQL injection and improve security. 1. Preprocessing statements separate SQL structure from data, send templates first and then pass parameters to avoid malicious input tampering with SQL logic; 2. PDO and MySQLi extensions commonly used in PHP realize preprocessing, among which PDO supports multiple databases and unified syntax, suitable for newbies or projects that require portability; 3. MySQLi is specially designed for MySQL, with better performance but less flexibility; 4. When using it, you should select appropriate placeholders (such as? or named placeholders) and bind parameters through execute() to avoid manually splicing SQL; 5. Pay attention to processing errors and empty results to ensure the robustness of the code; 6. Close it in time after the query is completed.
    PHP Tutorial . Backend Development 616 2025-07-12 03:13:11
  • How Do You Handle Authentication and Authorization in PHP?
    How Do You Handle Authentication and Authorization in PHP?
    TohandleauthenticationandauthorizationinPHP,usesessionsfortrackingusers,hashpasswordssecurely,implementrole-basedaccesscontrol,andmaintainup-to-datesecuritypractices.1.UsePHPsessionstostoreuseridentificationafterloginandverifyloginstatusacrosspages.2
    PHP Tutorial . Backend Development 982 2025-07-12 03:11:20
  • How to set and get session variables in PHP?
    How to set and get session variables in PHP?
    To set and get session variables in PHP, you must first always call session_start() at the top of the script to start the session. 1. When setting session variables, use $_SESSION hyperglobal array to assign values ??to specific keys, such as $_SESSION['username']='john_doe'; it can store strings, numbers, arrays and even objects, but avoid storing too much data to avoid affecting performance. 2. When obtaining session variables, you need to call session_start() first, and then access the $_SESSION array through the key, such as echo$_SESSION['username']; it is recommended to use isset() to check whether the variable exists to avoid errors
    PHP Tutorial . Backend Development 750 2025-07-12 03:10:20

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