During PHP development, we often encounter this situation: using mysqli_connect() or PDO to successfully connect to the database, but encounter errors when executing SQL queries, such as returning false, no results, and even program crashes. This problem may seem like a problem with database connections at first glance, but the cause may be very complicated in reality. This article will take you to analyze the possible causes of this phenomenon one by one and provide corresponding solutions.

In PHP projects, password encryption is an important part of ensuring the security of user data. The two common password encryption methods are the crypt() function and the password_hash() function. So, which one should I choose? What is the difference between them? This article will analyze the characteristics of these two in detail to help you make a more suitable choice.

In PHP programming, database connection is a very basic and important step, and is usually implemented using connect() functions (such as mysqli_connect() or PDO connection methods). The correct username and password are one of the key factors in successfully establishing a connection. If the username or password is spelled incorrectly, a connection failure is an inevitable result. This article will explain the reasons behind it in detail and use PHP code examples to illustrate it.

In PHP's session module, session_register_shutdown() is a relatively special and less well-known function. Its original design intention and function are mainly closely related to the request life cycle of PHP and the secure storage of session data. This article will analyze in detail why this function is designed and its specific role in session management.

When using PHP's GD library for image processing, sometimes we need to set a transparent background for the image, such as making the background transparent when generating PNG images instead of filling in white or black. To achieve this effect, you can mainly use the two functions imagecolorallocatealpha() and imagefill().

In network programming, PHP is not only used to develop web applications, it can also be used to create low-level network communication programs, such as TCP servers. socket_accept() is one of the important functions in PHP to accept client connections. This article will take you to build a simple TCP server step by step and explain the key points.

When using the mysqli extension of PHP for database operations, mysqli_stmt::attr_get is a relatively unpopular but practical function. It is used to get the properties of the current statement handle and is usually used to debug or diagnose underlying behavior. In order to understand the execution effect of this function more clearly, we can use debugging tools to observe its internal working process.

When storing user input content using MySQL database, especially text fields such as comments, nicknames, and chat records, we often encounter a problem: when the user enters an Emoji emoticon or some special Unicode symbol, saving to the database will fail, or even if the save is successful, it will be garbled or question marks (?).

Use cURL extensions to perform HTTP requests and other network operations. To set up sharing multiple cURL requests, we can use the curl_share_init function to initialize a Share Handle, and then use curl_share_strerror() to diagnose error messages for the shared handle. Next, we will explain in detail how to use these functions.

When using PHP's GD library for image processing, the imageantialias() function is often used to turn off anti-aliasing to smooth out the drawn lines. Many developers will wonder whether this function needs to be called again every time an image is drawn? Or are there best practices to avoid duplicate calls to improve performance?

When connecting to a database using PHP, the connect() function (such as mysqli_connect() or PDO connection) returns successfully, meaning that the database server has successfully accepted the connection request. However, even if the connection is successful, it is still possible that a specific database table cannot be accessed due to insufficient permissions. This is a common confusion for many developers when debugging database permission issues.

The get_defined_constants() function returns an associative array containing all the constants defined in the current environment. Normally, you can get the names and values ​​of most constants through this function. It is suitable for obtaining built-in constants in the system, user-defined constants, etc.

When using PHP's mysqli extension to process database operations, the mysqli_stmt::attr_get function is used to obtain the properties of the preprocessing statement object. However, developers often encounter situations where this function returns unexpected data, resulting in confusion or even errors in the program logic. This article will combine PHP code examples to analyze the cause of the exception returned by mysqli_stmt::attr_get function, and give corresponding solutions.

When developing PHP applications, it is usually necessary to interact with the MySQL database, and character set settings directly affect encoding issues during data storage and retrieval. To ensure that database connections use the correct character set, the mysqli::get_charset function provides a convenient way to detect the character set of the current database connection. This article will describe how to use this function to detect the connection character set of a remote database.

The get_defined_constants function is one of the built-in functions of PHP, which is used to return all constants defined in the current script. It returns an associative array containing the constant name and its value. Through this function, developers can view defined constants anywhere in the program, making it easier to debug and analyze constant changes.

The mysqli_stmt class is the core component used to execute prepared statements, while the attr_get function is used to obtain the properties of the preprocessed statement. With the evolution of PHP versions, especially from PHP 7 to PHP 8, the support and performance of the mysqli_stmt::attr_get function has also changed significantly. This article will analyze the differences between these two versions in detail in this function to help developers better understand and apply them.

cURL is a very powerful tool that can be used to make various network requests. curl_init() is a function used to initialize a cURL session, while curl_share_init() is used to initialize a shared session. Through these two functions, we can implement different session sharing and data exchange, thereby improving efficiency.

PHP provides the get_defined_constants() function, which can return all defined constants in the current script. The function returns an associative array where the key is the name of the constant and the value is the value of the constant. For example:

socket_accept() is a key function to implement server-side socket communication. Through it, we can accept connection requests initiated by the client and further transmit and receive data. In this article, we will build a simple FTP-like file transfer service based on the socket extension of native PHP, demonstrating how to implement basic file upload and download functions.