PHP mysqli_fetch_field() 函数

定义和用法

PHP 结果对象（类 mysqli_result）表示 MySQL 结果，由 SELECT 或 DESCRIBE 或 EXPLAIN 查询返回。

mysqli_fetch_field() 函数接受结果对象作为参数，并以对象的形式返回下一列/字段的定义信息。

语法

mysqli_fetch_field($result);

参数

返回值

PHP mysqli_fetch_field() 函数返回一个包含给定结果中字段的定义信息的 object。如果没有任何信息，则此函数返回 FALSE。

返回的对象包含以下属性：

• name

• orgname

• table

• orgtable

• max_length

• length

• charsetnr

• flags

• type

• decimals

PHP 版本

此函数首次在 PHP 5 版本中引入，并在所有后续版本中均可使用。

示例

以下示例演示了 mysqli_fetch_field() 函数（过程式风格）的使用：

<?php
   $con = mysqli_connect("localhost", "root", "password", "mydb");

   mysqli_query($con, "CREATE TABLE myplayers(ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Place_Of_Birth VARCHAR(255), Country VARCHAR(255))");
   print("Table Created.....\n");
   mysqli_query($con, "INSERT INTO myplayers values(1, 'Sikhar', 'Dhawan', 'Delhi', 'India')");
   mysqli_query($con, "INSERT INTO myplayers values(2, 'Jonathan', 'Trott', 'CapeTown', 'SouthAfrica')");
   mysqli_query($con, "INSERT INTO myplayers values(3, 'Kumara', 'Sangakkara', 'Matale', 'Srilanka')");
   print("Record Inserted.....\n");

   //Retrieving the contents of the table
   $res = mysqli_query($con, "SELECT * FROM myplayers");

   //Fetching the fields
   while($info = mysqli_fetch_field($res)){
      //Current field
      $currentfield = mysqli_field_tell($res);
      print("Current Field: ".$currentfield."\n");
      print("Name: ".$info->name."\n");
      print("Type: ".$info->type."\n");
   }

   //Closing the statement
   mysqli_free_result($res);

   //Closing the connection
   mysqli_close($con);
?>

这将产生以下结果：

Table Created.....
Record Inserted.....
Current Field: 1
Name: ID
Type: 3
Current Field: 2
Name: First_Name
Type: 253
Current Field: 3
Name: Last_Name
Type: 253
Current Field: 4
Name: Place_Of_Birth
Type: 253
Current Field: 5
Name: Country
Type: 253

示例

在面向对象风格中，此函数的语法为 $result->fetch_field; 以下是此函数在面向对象风格中的示例：

<?php
   //Creating a connection
   $con = new mysqli("localhost", "root", "password", "mydb");

   $con -> query("CREATE TABLE Test(Name VARCHAR(255), AGE INT)");
   $con -> query("insert into Test values('Raju', 25),('Rahman',  30),('Sarmista', 27)");
   print("Table Created.....\n");

   $stmt = $con -> prepare( "SELECT * FROM Test WHERE Name in(?, ?)");
   $stmt -> bind_param("ss", $name1, $name2);
   $name1 = 'Raju';
   $name2 = 'Rahman';

   //Executing the statement
   $stmt->execute();

   //Retrieving the result
   $result = $stmt->get_result();

   //Current Field
   while($info = $result->fetch_field()){
      $field = $result->current_field;
      print("Current Field: ".$field."\n");
      print("Field Name: ".$info->name."\n");
   }

   //Closing the statement
   $stmt->close();

   //Closing the connection
   $con->close();
?>