PHP mysqli_fetch_field_direct() 函式

定義和用法

PHP 結果物件（mysqli_result 類）表示由 SELECT 或 DESCRIBE 或 EXPLAIN 查詢返回的 MySQL 結果。

mysqli_fetch_field_direct() 函式接受結果物件和表示欄位編號的整數作為引數，並以物件的格式返回指定列/欄位的定義資訊。

語法

mysqli_fetch_field_direct($result, $field);

引數

返回值

PHP mysqli_fetch_field_direct() 函式返回一個包含指定欄位定義資訊的 物件。如果指定的欄位（編號）不可用，則此函式返回 FALSE。

返回的物件包含以下屬性：

• name

• orgname

• table

• orgtable

• max_length

• length

• charsetnr

• flags

• type

• decimals

PHP 版本

此函式首次引入於 PHP 5 版本，並在所有後續版本中均有效。

示例

以下示例演示了 mysqli_fetch_field_direct() 函式（過程式風格）的用法：

<?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 metadata of 3rd field
   $info = mysqli_fetch_field_direct($res, 2);

   print("Name: ".$info->name."\n");
   print("Table: ".$info->table."\n");
   print("Max Length: ".$info->max_length."\n");
   print("Flags: ".$info->flags."\n");
   print("Type: ".$info->type."\n");
   print("Definition: ".$info->def."\n");
   print("Character Set: ".$info->charsetnr."\n");

   //Closing the statement
   mysqli_free_result($res);

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

這將產生以下結果：

Table Created.....
Record Inserted.....
Name: Last_Name
Table: myplayers
Max Length: 10
Flags: 0
Type: 253

示例

在面向物件風格中，此函式的語法為 $result->fetch_field_direct();以下是此函式在面向物件風格中的示例：

<?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();

   //Fetching the metadata of 2nd field
   $info = $result->fetch_field_direct(1);

   print("Name: ".$info->name."\n");
   print("Table: ".$info->table."\n");
   print("Max Length: ".$info->max_length."\n");
   print("Flags: ".$info->flags."\n");
   print("Type: ".$info->type."\n");
   print("Definition: ".$info->def."\n");
   print("Character Set: ".$info->charsetnr."\n");

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

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

這將產生以下結果：

Table Created.....
Name: AGE
Table: Test
Max Length: 0
Flags: 32768
Type: 3
Definition:
Character Set: 63