How to use thinkphp5 to print error SQL statements to the log

1. Reasons for wrong SQL statements

Wrong SQL statements are difficult to avoid in applications. These errors are sometimes difficult to identify. Use thinkphp5 to A more elegant way to catch and handle these errors. During the development process, incorrect SQL statements may be caused by the following reasons:

1. SQL syntax error

The causes of SQL syntax errors are usually The SQL statement you wrote contains errors or is incomplete. This is one of the most common mistakes as even the most experienced developers make syntax mistakes.

2. Database connection problem

The application's failure to connect to the database is due to a database connection problem, which may result in SQL statement errors. Such problems are usually caused by incorrect database settings, the database server not being started, or the request being unable to be processed.

3. Database table structure error

If there is an error in the database table structure, the SQL query may not be completed, and the result must be wrong. . One of the common mistakes is that when the table structure changes, the fields in the query may not match the table where the fields have been deleted or changed.

2. How to print erroneous SQL statements into the log

In ThinkPHP5, we can use the logging function to capture and analyze erroneous SQL statements. Saving erroneous SQL statements can help us find problems faster and handle SQL errors better.

The following is an example that demonstrates how to set up logging and capture error SQL statements:

First, you need to add the following configuration to the application's config.php file:

// 开启SQL日志记录
'trace' => [
    // 记录SQL日志
    'type' => 'sql',
    // SQL日志记录方式
    'record_sql' => true,
],

This will enable SQL logging and allow erroneous SQL statements to be logged. To ensure recording SQL queries must set 'record_sql' => true. If the value is false, SQL queries will not be logged and exceptions will not be logged.

After setting up the configuration, we can run the application and view the log file. By using logging, we can easily find and resolve bad SQL statement issues.

3. Other debugging techniques

In addition to using logging, there are other techniques that can help us capture and identify error SQL statements:

1. Use the Debug tool

Debug is an integrated tool that can help you identify incorrect SQL statements and other problems, and it is provided by ThinkPHP5. Simply set debug mode and access the application to use the Debug tool.

2. Print SQL Errors

By using try-catch blocks and Exceptions, we can catch SQL errors and print them out:

try {
    // 执行查询操作
} catch (\Exception $e) {
    // 打印错误到控制台
    echo $e->getMessage();
}

Since database query errors are usually related to SQL syntax errors, we can print the errors to the console to further determine the root cause of the problem.

3. Debugging with PHPMyAdmin

If you use MySQL as the database, PHPMyAdmin can be used as a general debugging tool. Through PHPMyAdmin's visual interface, we can easily view and analyze SQL queries.

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