Question

我有问题使$ dbh1可用于需要查询的所有php文件。我尝试在查询运行的文件中使用“global $ dbh1”。

我有4个文件：testswitchDB3.php（main），testconnect.php，login.php和testnumcards.php

数据库连接后，由login.php和testconnect.php运行。两个文件都正常工作

因此，通过将“global $ dbh1”应用于testnumcards.php，可以创建并使用$ dbh1。

但它不起作用。以下是我的代码。

testswitchDB3.php

<!DOCTYPE html>
<html>
<head>
    <title>Test the switching responses between databases using buttons</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <link rel="stylesheet" href="../dojo1_8/dijit/themes/soria/soria.css"/>
    <link rel="stylesheet" href="../common.css"/>
    <style type="text/css">
        html, body 
    {
            width: 100%;
            height: 100%;
            margin: 5px;
            padding: 0px;
            overflow: hidden; /* No Scrollbar */
        }
    </style>
    <script>            
    var dojoConfig =
        {
              parseOnLoad: true,
              isDebug: true,
              async: true,//
              locale : "en-us"//
        }; 
    </script>
    <script src='../dojo1_8/dojo/dojo.js'></script>
</head>

<body class="soria">
<div id="main_bContainer" data-dojo-type="dijit.layout.BorderContainer" data-dojo-props="design:'sidebar'">
<div id="cp_Center" data-dojo-type="dijit/layout/ContentPane" data-dojo-props="region:'center'">
<table>
    <tr>
     <td>
      <div id=btn1></div><!--for testdata2060_03-->
     </td>
     <td>
      <div id=btn2></div><!--for testdata2060_10-->
     </td>
     <td>
      <div id=btn3></div><!--for testdata2060_05-->
     </td>
    </tr>
    <tr>
     <td>
      <div id=btn4></div><!--for testdata2060_03-->
     </td>
     <td>
      <div id=btn5></div><!--for testdata2060_10-->
     </td>
     <td>
      <div id=btn6></div><!--for testdata2060_05-->
     </td>
    </tr>
    <tr>
     <td>
      <div id=btn7></div><!--for testdata2060_03-->
     </td>
     <td>
      <div id=btn8></div><!--for testdata2060_10-->
     </td>
     <td>
      <div id=btn9></div><!--for testdata2060_05-->
     </td>
    </tr>
 </table>
<div id=statement></div>
</div><!--cp_Center-->
</div><!--main_bContainer-->

<script>
    require(["dojo/parser", "dijit/layout/BorderContainer", "dijit/form/Button",
    "dojo/on", "dijit/form/Select", "dojo/store/Memory", "dojo/request", 
    "dojo/dom", "dojo/dom-construct", "dojo/domReady!"],
    function(parser, BorderContainer, Button, on, Select, Memory, request, dom, 
    domConstruct)
    {var commonDB = "nameless"; function connect(commonDB)
        {request.post("testconnect.php",
            {data:{nameDB : commonDB}
            //,handleAs:"json"//without the use of "handleAs:JSON" as it needs only 
            confirnation or not 
             }).then
        (function(connect)
            {console.debug("data read as: ", connect);
    if(connect)//as true or false as indicated in login.php 
            {alert("Successfully login and connected");
            switch(commonDB)
                {
                 case 'testdata2060_03':
                    btn4.set('disabled', false);
                    btn5.set('disabled', true);
                    btn6.set('disabled', true);
                    btn7.set('disabled', false);
                    btn8.set('disabled', true);
                    btn9.set('disabled', true);
                    break;
                 case 'testdata1970_11':
                    btn4.set('disabled', true);
                    btn5.set('disabled', false);
                    btn6.set('disabled', true);
                    btn7.set('disabled', true);
                    btn8.set('disabled', false);
                    btn9.set('disabled', true);
                    break;
                 case 'testdata1970_05':
                    btn4.set('disabled', true);
                    btn5.set('disabled', true);
                    btn6.set('disabled', false);
                    btn7.set('disabled', true);
                    btn8.set('disabled', true);
                    btn9.set('disabled', false);
                    break;
                }}  
             else
                alert("Attempt to login and connect is NOT successful");
                },


            (
              function(error)
                {
                    alert("Test's Error:"+error);
                    console.debug(error);
                }
        );
       }

       function card(commonDB)
        {request.post("testnumcards.php",
          {
          //{data:{xxx:yyy},
           handleAs: "json"
          }).then
         (function(response)
             {alert("The number of the distinct catds for "+commonDB+" is "+response);
               dom.byId("statement").innerHTML = "The number of the distinct catds for
               "+commonDB+" is "+response;
              },
          function(error)
              {alert("Test's Error:"+error);
               console.debug(error);
              }
         )}

/*
function test()
{
}
*/

var btn1 = new Button // Button, not button
({  label: "testdata2060_03",
    onClick: function()
     {
         console.log("Console Log: Button1 has been clicked.");
         connect('testdata2060_03');
     }
 },"btn1"); 
btn1.startup();

var btn2 = new Button
({label: "testdata1970_11"
 },"btn2");
btn2.startup();

var btn3 = new Button
({label: "testdata1970_05"
  },"btn3");
btn3.startup();

var btn4 = new Button // Button, not button
({label: "Number of cards",
    disabled: true
 },"btn4"); 
btn4.startup();

var btn5 = new Button
({label: "Number of cards",
    disabled: true
 },"btn5");
btn5.startup();

var btn6 = new Button
({label: "Number of cards",
    disabled: true
 },"btn6");
btn6.startup();

var btn7 = new Button // Button, not button
({label: "Number of tests",
    disabled: true
 },"btn7"); 
btn7.startup();

var btn8 = new Button
({label: "Number of tests",
   disabled: true
},"btn8");
btn8.startup();

var btn9 = new Button
({label: "Number of tests",
   disabled: true
},"btn9");
btn9.startup();

/*on(btn1, 'click', function()
{console.log("Console Log: Button1 has been clicked.");
 connect('testdata2060_03');
});
*/

on(btn2, 'click', function()
{console.log("Console Log: Button2 has been clicked.");
connect('testdata1970_11');
});

on(btn3, 'click', function()
{console.log("Console Log: Button3 has been clicked.");
connect('testdata1970_05');
});

on(btn4, 'click', function()
{console.log ("Console Log: Button4 has been clicked.");
card();
});

on(btn5, 'click', function()
{console.log("Console Log: Button5 has been clicked.");
test();
});

on(btn6, 'click', function()
{console.log("Console Log: Button6 has been clicked.");
card();
});

on(btn7, 'click', function()
{console.log("Console Log: Button7 has been clicked.");
test();
});

on(btn8, 'click', function()
{console.log("Console Log: Button8 has been clicked.");
card();
});

on(btn9, 'click', function()
{console.log("Console Log: Button9 has been clicked.");
test();
});

});
</script>
</body>

接下来是testconnect.php

<?php
global $dbh1;
$dbname = $_POST['nameDB']; 
require_once '../scripts/login.php';
echo $connect;
?>

接下来是login.php

<?php
    global $dbname;
    global $dbh1;

    $dbh1 =  null; 
    $dsn ="mysql:host=localhost; dbname=$dbname";
    $user ='root';
    $pswd ='';

 try
    {
     $dbh1 = new PDO($dsn, $user, $pswd, array(PDO::ATTR_TIMEOUT => "10",// 10 seconds
     PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION)); // connect to DB, declared as global variable!
     $connect = TRUE;
    }

catch(PDOException $err)
    {
     $alertmsg = $err->getMessage();
     $connect = FALSE;
    }

echo $connect;      
?>

接下来是testnumcards.php

<?php
 global $dbh1;

 $stmt = $dbh1->prepare("select count(distinct mfg_code)as mfg_code from test");

 try
  {
    $stmt->execute();
  }

catch(PDOException $err)
 {
   $alertmsg = $err->getMessage();
 }

$num = $stmt->fetch(PDO::FETCH_ASSOC);
echo $num['mfg_code'];

?>

您可以参考JsFiddle作为参考，但如果没有PHP支持则无法使用。

Answer 1

您需要使用

启动文件

<?php
require("login.php");

在所有php脚本中，他们可以使用连接，除非这些脚本已经包含或需要该文件。

每次请求都必须创建连接，因为请求结束时，连接将被关闭。因此，当您请求testnumcards.php时，没有$ dbh1来声明全局，因为它尚未在该请求上设置

修改

每次向服务器发送新请求时，PHP都是一种请求特定语言，它需要再次创建连接并设置变量，一页不知道在另一页中创建的资源，因为所有资源都在请求之间关闭

因此，如果我转到page1.php并连接到数据库，当我稍后转到page2.php时，除非我再次创建该连接，否则它与数据库没有连接。当page1.php完成然后连接关闭时，您需要再次在page2.php中连接

这就是为什么大多数脚本首先需要一个文件来设置他们需要的任何连接或其他资源

使$ dbh1（数据库句柄）可用于所有php文件

testswitchDB3.php

接下来是testconnect.php

接下来是login.php

接下来是testnumcards.php

1 个答案: