PHP mysqli field_seek() 函数

定义和用法

field_seek() / mysqli_field_seek() 函数将字段光标设置为给定的字段偏移量。

实例

例子 1 - 面向对象风格

将字段光标设置为结果集中的第二列（"Age"），使用 fetch_field() 获取字段信息，然后打印字段的名称、表和最大长度：

<?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)) {

  // 获取第二列的字段信息
  $result = field_seek(1);
  $fieldinfo = $result -> fetch_field();

  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();
?>

例子 2 - 过程式风格

将字段光标设置为结果集中的第二列（"Age"），使用 mysqli_fetch_field() 获取字段信息，然后打印字段的名称、表和最大长度：

<?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)) {

  // 获取第二列的字段信息
  mysqli_field_seek($result, 1);
  $fieldinfo = mysqli_fetch_field($result);

  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);
?>

语法

面向对象风格：

$mysqli_result -> field_seek(fieldnr)

过程式风格：

mysqli_field_seek(result, fieldnr)

技术细节