PHP mysqli_stmt_result_metadata()用法及代码示例

定义和用法

这个mysqli_stmt_result_metadata()函数接受准备好的语句对象作为参数，如果给定的语句执行 SELECT 查询(或任何其他返回结果集的查询)，它(此函数)返回一个元数据对象，该对象保存有关给定语句的结果集的信息。

用法

mysqli_stmt_result_metadata($stmt);

参数

Sr.No	参数及说明
1	con(Mandatory) 这是一个表示准备好的语句的对象。

返回值

PHP mysqli_stmt_result_metadata() 函数在成功时返回元数据对象，失败时返回 false。

PHP版本

这个函数最初是在 PHP 版本 5 中引入的，适用于所有后续版本。

示例

以下示例演示了 mysqli_stmt_result_metadata() 函数的用法(程序风格) -

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

   mysqli_query($con, "CREATE TABLE test(Name VARCHAR(255), age INT)");
   mysqli_query($con, "INSERT INTO test values('Raju', 25)");
   mysqli_query($con, "INSERT INTO test values('Jonathan', 30)");
   print("Table Created.....\n");

   //Retrieving the contents of the table
   $stmt = mysqli_prepare($con, "SELECT * FROM test");

   //Executing the statement
   mysqli_stmt_execute($stmt);

   //Retrieving the resultset metadata
   $metadata = mysqli_stmt_result_metadata($stmt);
   print_r(mysqli_fetch_fields($metadata));
 
   mysqli_free_result($metadata);

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

这将产生以下结果 -

Table Created.....
Array
(
    [0] => stdClass Object
        (
            [name] => Name
            [orgname] => Name
            [table] => test
            [orgtable] => test
            [def] =>
            [db] => mydb
            [catalog] => def
            [max_length] => 0
            [length] => 765
            [charsetnr] => 33
            [flags] => 0
            [type] => 253
            [decimals] => 0
        )

    [1] => stdClass Object
        (
            [name] => AGE
            [orgname] => AGE
            [table] => test
            [orgtable] => test
            [def] =>
            [db] => mydb
            [catalog] => def
            [max_length] => 0
            [length] => 11
            [charsetnr] => 63
            [flags] => 32768
            [type] => 3
            [decimals] => 0
        )

)

示例

在面向对象风格中，这个函数的语法是 $stmt->result_metadata();以下是面向对象样式 $minus 中此函数的示例；

<?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';
   print("Records Inserted.....\n");

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

   //Retrieving the resultset metadata
   $metadata = $stmt->result_metadata();

   $field = $metadata->fetch_field();
   print("Field Name:".$field->name);

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

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

这将产生以下结果 -

Table Created.....
Records Inserted.....
Field Name:Name