定义和用法

mysql_fetch_field() 函数从结果集中取得列信息并作为对象返回。

mysql_fetch_field() 可以用来从查询结果中取得字段的信息。如果没有指定字段偏移量，则提取下一个尚未被 mysql_fetch_field() 取得的字段。

该函数返回一个包含字段信息的对象。

被返回的对象的属性为：

• name - 列名
• table - 该列所在的表名
• max_length - 该列最大长度
• not_null - 1，如果该列不能为 NULL
• primary_key - 1，如果该列是 primary key
• unique_key - 1，如果该列是 unique key
• multiple_key - 1，如果该列是 non-unique key
• numeric - 1，如果该列是 numeric
• blob - 1，如果该列是 BLOB
• type - 该列的类型
• unsigned - 1，如果该列是无符号数
• zerofill - 1，如果该列是 zero-filled

语法

mysql_fetch_field(data,field_offset)

提示和注释

注释：本函数返回的字段名是区分大小写的。

例子

<?php
$con = mysql_connect("localhost", "hello", "321");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

$db_selected = mysql_select_db("test_db",$con);

$sql = "SELECT * from Person";
$result = mysql_query($sql,$con);

while ($property = mysql_fetch_field($result))
  {
  echo "Field name: " . $property->name . "<br />";
  echo "Table name: " . $property->table . "<br />";
  echo "Default value: " . $property->def . "<br />";
  echo "Max length: " . $property->max_length . "<br />";
  echo "Not NULL: " . $property->not_null . "<br />"; 
  echo "Primary Key: " . $property->primary_key . "<br />";
  echo "Unique Key: " . $property->unique_key . "<br />"; 
  echo "Mutliple Key: " . $property->multiple_key . "<br />";
  echo "Numeric Field: " . $property->numeric . "<br />";
  echo "BLOB: " . $property->blob . "<br />";
  echo "Field Type: " . $property->type . "<br />";
  echo "Unsigned: " . $property->unsigned . "<br />";
  echo "Zero-filled: " . $property->zerofill . "<br /><br />"; 
  }

mysql_close($con);
?>

输出：

Field name: LastName
Table name: Person
Default value: 
Max length: 8
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 0
BLOB: 0
Field Type: string
Unsigned: 0
Zero-filled: 0

Field name: FirstName
Table name: Person
Default value: 
Max length: 7
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 0
BLOB: 0
Field Type: string
Unsigned: 0
Zero-filled: 0

Field name: City
Table name: Person
Default value: 
Max length: 9
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 0
BLOB: 0
Field Type: string
Unsigned: 0
Zero-filled: 0

Field name: Age
Table name: Person
Default value: 
Max length: 2
Not NULL: 0
Primary Key: 0
Unique Key: 0
Mutliple Key: 0
Numeric Field: 1
BLOB: 0
Field Type: int
Unsigned: 0
Zero-filled: 0