English
English
In PHP development, when operating a database, you often need to obtain field information, such as field name, type, length, etc. This is especially common in scenarios such as generating dynamic tables and exporting data. mysql_fetch_field and mysqli_fetch_field are two functions used to obtain field definition information. They have certain functional similarities, but due to the evolution of PHP, there are obvious differences. This article will analyze their differences, functions and usage in detail.
mysql_fetch_field belongs to PHP's mysql extension. It was introduced in PHP 4 and is mainly used to obtain field information from the result set. However, starting with PHP 7.0.0, the mysql extension has been completely removed , meaning mysql_fetch_field is no longer available. Therefore, this function can only be used in old versions of PHP and is no longer recommended for new projects.
In order to solve the limitations of mysql extension, PHP has introduced a new mysqli (MySQL Improved) extension since 5.0, providing stronger functionality and better security. mysqli_fetch_field is part of this extension, providing similar field information acquisition capabilities, and supports both object-oriented and procedural usages.
grammar:
object mysql_fetch_field(resource $result, int $field_offset = 0)
Sample code:
$conn = mysql_connect("localhost", "user", "password");
mysql_select_db("testdb", $conn);
$result = mysql_query("SELECT * FROM users");
$field = mysql_fetch_field($result);
echo $field->name;
?? Note: This method is deprecated, and an error will be reported when running on PHP 7 and above.
