php - 我应该使用什么值？ (根据该变量选择是否显示表数据)

Question

form1.php

<?php
$connection = mysql_connect("localhost","root","")
or die ("Couldn't Connect To Server");
$query = "CREATE DATABASE IF NOT EXISTS db1";
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());
$db = mysql_select_db("db1", $connection)
or die ("Couldn't Select Database");
$query = "CREATE TABLE IF NOT EXISTS table1 (fname VARCHAR(20), lname VARCHAR(20), mail VARCHAR(20))";
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());
function insertvalues (){if ( isset ($_POST['fname']{0}, $_POST['lname']{0}, $_POST['mail']{0}) ){
   $query = "INSERT INTO table1 (fname, lname, mail) VALUES ('".$_POST[fname]."', '".$_POST[lname]."', '".$_POST[mail]."')"; 
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());
}
else{
   echo "No Values Entered. Please Press Back In Your Browser And Enter Some Values.";
}}
$value1 = "";

if isset($value1) {$query = "SELECT * FROM table1";
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());
    echo "<TABLE BORDER = '1'>";
    echo "<TR>";
    echo "<TH>First Name</TH><TH>Last Name</TH><TH>Mail</TH>";
    echo "</TR>";    
while ($row = mysql_fetch_array($result))
     {
echo "<TR>";
echo "<TD>", $row['fname'], "</TD><TD>",
$row['lname'], "</TD><TD>",
$row['mail'], "</TD>";
echo "</TR>";  
     }
    echo "</TABLE>";}

    else {
        echo "<BR>No Table".
    }

    mysql_close($connection);
?>

我正在考虑将什么放入 $value1 中。如何检查是否“未输入任何值。请在浏览器中按返回键并输入一些值。”显示错误，如果是，不显示表格？

Answer 1

这是你要的吗？

<?php
$connection = mysql_connect("localhost","root","")
or die ("Couldn't Connect To Server");
$query = "CREATE DATABASE IF NOT EXISTS db1";
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());
$db = mysql_select_db("db1", $connection)
or die ("Couldn't Select Database");
$query = "CREATE TABLE IF NOT EXISTS table1 (fname VARCHAR(20), lname VARCHAR(20), mail VARCHAR(20))";
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());


function insertvalues (){if ( isset ($_POST['fname']{0}, $_POST['lname']{0}, $_POST['mail']{0}) ){
   $query = "INSERT INTO table1 (fname, lname, mail) VALUES ('".$_POST[fname]."', '".$_POST[lname]."', '".$_POST[mail]."')"; 
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());

return true;
}
else{
   echo "No Values Entered. Please Press Back In Your Browser And Enter Some Values.";
   return false;
}}


$value1 = insertvalues();

if isset($value1) {$query = "SELECT * FROM table1";
$result = mysql_query($query)
or die ("Query Failed: " . mysql_error());
    echo "<TABLE BORDER = '1'>";
    echo "<TR>";
    echo "<TH>First Name</TH><TH>Last Name</TH><TH>Mail</TH>";
    echo "</TR>";    
while ($row = mysql_fetch_array($result))
     {
echo "<TR>";
echo "<TD>", $row['fname'], "</TD><TD>",
$row['lname'], "</TD><TD>",
$row['mail'], "</TD>";
echo "</TR>";  
     }
    echo "</TABLE>";}

    else {
        echo "<BR>No Table".
    }

    mysql_close($connection);
?>

与您的代码的不同之处在于，如果成功插入，我会添加一个返回值 true，否则会添加 false。并将该值赋给 $value1。

如果我可以的话......这段代码有一些严重的性能和其他问题，从电子邮件开始通常需要超过 20 个字符，并且运行创建数据库，在每次运行时创建表查询......等等。