定義和用法

mysql_fetch_field() 函數(shù)從結(jié)果集中取得列信息并作為對象返回。

mysql_fetch_field() 可以用來從查詢結(jié)果中取得字段的信息。如果沒有指定字段偏移量，則提取下一個尚未被 mysql_fetch_field() 取得的字段。

該函數(shù)返回一個包含字段信息的對象。

被返回的對象的屬性為：

• name - 列名
• table - 該列所在的表名
• max_length - 該列最大長度
• not_null - 1，如果該列不能為 NULL
• primary_key - 1，如果該列是 primary key
• unique_key - 1，如果該列是 unique key
• multiple_key - 1，如果該列是 non-unique key
• numeric - 1，如果該列是 numeric
• blob - 1，如果該列是 BLOB
• type - 該列的類型
• unsigned - 1，如果該列是無符號數(shù)
• zerofill - 1，如果該列是 zero-filled

語法

mysql_fetch_field(data,field_offset)

參數(shù)	描述
data	必需。要使用的數(shù)據(jù)指針。該數(shù)據(jù)指針是從 mysql_query() 返回的結(jié)果。
field_offset	必需。規(guī)定從哪個字段開始。0 指示第一個字段。如果未設(shè)置，則取回下一個字段。

提示和注釋

注釋：本函數(shù)返回的字段名是區(qū)分大小寫的。

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);
?>

輸出：

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