PHP mysqli fetch_field_direct() 函数
示例 - 面向对象的样式
返回结果集中某个单一字段（列）的 meta-data，并输出字段名称、表格和最大长度：
<?php
$mysqli = new mysqli("localhost","my_user","my_password","my_db");
if ($mysqli -> connect_errno) {
echo "Failed to connect to MySQL: " . $mysqli -> connect_error;
exit();
}
$sql = "SELECT Lastname, Age FROM Persons ORDER BY Lastname";
if ($result = $mysqli -> query($sql)) {
// Get field information for column "Age"
$fieldinfo = $result -> fetch_field_direct(1);
printf("Name: %s\n", $fieldinfo -> name);
printf("Table: %s\n", $fieldinfo -> table);
printf("Max. Len: %d\n", $fieldinfo -> max_length);
$result -> free_result();
}
$mysqli -> close();
?>
$mysqli = new mysqli("localhost","my_user","my_password","my_db");
if ($mysqli -> connect_errno) {
echo "Failed to connect to MySQL: " . $mysqli -> connect_error;
exit();
}
$sql = "SELECT Lastname, Age FROM Persons ORDER BY Lastname";
if ($result = $mysqli -> query($sql)) {
// Get field information for column "Age"
$fieldinfo = $result -> fetch_field_direct(1);
printf("Name: %s\n", $fieldinfo -> name);
printf("Table: %s\n", $fieldinfo -> table);
printf("Max. Len: %d\n", $fieldinfo -> max_length);
$result -> free_result();
}
$mysqli -> close();
?>
查看底部的程序样式示例。
定义和用法
fetch_field_direct() / mysqli_fetch_field_direct() 函数从结果集中取得某个单一字段（列）的 meta-data，并作为对象返回。
语法
面向对象的风格：
$mysqli_result -> fetch_field_direct(fieldnr)
程序风格：
mysqli_fetch_field_direct(result, fieldnr)
参数值
| 参数 | 描述 |
|---|---|
| result | 必需。规定由 mysqli_query()、mysqli_store_result() 或 mysqli_use_result() 返回的结果集标识符。 |
| fieldnr | 必需。规定字段号。必须介于 0 和 字段数-1 之间。 |
技术细节
| 返回值: | 返回包含字段定义信息的对象。如果没有可用信息则返回 FALSE。该对象有下列属性：
|
|---|---|
| PHP 版本: | 5+ |
示例 - 程序样式
返回结果集中某个单一字段（列）的 meta-data，并输出字段名称、表格和最大长度：
<?php
$con = mysqli_connect("localhost","my_user","my_password","my_db");
if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit();
}
$sql = "SELECT Lastname, Age FROM Persons ORDER BY Lastname";
if ($result = mysqli_query($con, $sql)) {
// Get field information for column "Age"
$fieldinfo = mysqli_fetch_field_direct($result, 1);
printf("Name: %s\n", $fieldinfo -> name);
printf("Table: %s\n", $fieldinfo -> table);
printf("Max. Len: %d\n", $fieldinfo -> max_length);
mysqli_free_result($result);
}
mysqli_close($con);
?>
$con = mysqli_connect("localhost","my_user","my_password","my_db");
if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit();
}
$sql = "SELECT Lastname, Age FROM Persons ORDER BY Lastname";
if ($result = mysqli_query($con, $sql)) {
// Get field information for column "Age"
$fieldinfo = mysqli_fetch_field_direct($result, 1);
printf("Name: %s\n", $fieldinfo -> name);
printf("Table: %s\n", $fieldinfo -> table);
printf("Max. Len: %d\n", $fieldinfo -> max_length);
mysqli_free_result($result);
}
mysqli_close($con);
?>
