Learn how to diagnose and resolve frequent connection-related issues when initiating transactions with mysqli::begin_transaction() in MySQL. This guide covers connectivity, permissions, engine compatibility, autocommit settings, error handling, network checks, and log analysis.

The fundamental concept of a transaction is “either all succeed or all fail.” If one operation in a transaction fails, all operations within it will be rolled back (undone). Transactions generally follow four key characteristics, known as the ACID principles:

In PHP development, it’s common to interact with MySQL databases. The functionality of the database depends not only on the server version but also on the client library. This article introduces how to use mysqli::$client_version to check whether your MySQL client supports the latest features.

When developing PHP applications, especially those involving database operations, obtaining MySQL-related configuration information is often very important. In particular, when troubleshooting database connection issues or optimizing database performance, understanding the MySQL client version and related configuration details is crucial. PHP offers multiple methods to retrieve this information, with mysqli::$client_version and phpinfo() being two very useful tools. This article explores how to combine these two functions to obtain a more comprehensive MySQL configuration overview.

First, it is important to clarify that mysqli::$client_version returns the version of the client library used for communication between PHP and MySQL, not the version number of the MySQL server. This is a common misunderstanding, as many developers mistakenly believe that it returns the version corresponding to the MySQL server.

How to Use mysqli::$client_version to Retrieve and Verify MySQL Client Version Information?

Monitoring the execution status of SQL queries is crucial for debugging and optimizing PHP applications. This article explains how to use the mysqli::$info function to track SQL execution in real time, providing detailed insights into affected rows, warnings, and other query information.

What is mysqli::$info? mysqli::$info is a read-only property that returns the detailed information generated by the recently executed query. It is usually used in UPDATE, DELETE, or INSERT ... ON DUPLICATE KEY UPDATE statement to provide information such as the number of affected rows, warnings, etc.

1. Introduction to mysqli_error() mysqli_error() is one of the most familiar error handling functions for developers. Its function is to return a string describing the error when the database operation fails. For example, when executing an incorrect SQL statement:

When using PHP for MySQL database operations, developers usually pay more attention to the query results themselves, such as the number of rows returned or whether the execution is successful, and it is easy to ignore a useful debugging tool - the mysqli::$info attribute. After some types of SQL statements are executed, this property can return more statistics about the execution results, helping us to understand the impact of a query more comprehensively.

1. The essential difference between PDO and mysqli connection errors: Connection and query errors are reported through the exception mechanism (PDOException). The code can be captured using try...catch, and the exception information contains detailed error descriptions.

When using PHP to interact with a MySQL database, you might encounter mysqli::$connect_error returning garbled text. This issue is usually caused by incorrect character encoding settings, resulting in unreadable error messages from the database.

The $connect_error property is an important debugging tool when using PHP's mysqli extension for database connections. When the connection to the database fails, it should return an error message. However, many developers find that when debugging database connection problems: mysqli::$connect_error returns one. This is confusing and is not conducive to the rapid positioning of the problem. This article will analyze in detail the reasons that may cause this phenomenon and provide corresponding solutions.

When using PHP’s mysqli extension to connect to a MySQL database, connection failures are quite common. Typically, we check the connection error code and message to determine the root cause. However, sometimes we also want to retrieve some server information—like the MySQL server version—to assist in diagnosis.

This article discusses the common causes of mysqli::$server_info returning an empty value, provides solutions to common errors, and offers improved code examples.