发信人: netiscpu (网中鸟~~flying), 信区: Linux
标 题: [中英]PHP/MySQL教程(3-2)Stay Informed
发信站: 紫 丁 香 (Mon Jan 17 04:12:44 2000) WWW-POST
[中英]PHP/MySQL教程(3-2)Stay Informed
[原作者] Graeme Merrall
[出处] http://hotwired.lycos.com/webmonkey/programming/php/tutorials/tutorial4
.html
[译者] netiscpu
PHP/MySQL Tutorial
by Graeme Merrall
======================================================================
3-2 Stay Informed (不知道怎么翻译,保留原标题吧;)
请看下面这个程序:
-------------------------begin of exam3-2a.php3----------------------
<html>
<body>
<?php
$db = mysql_connect("localhost", "root");
mysql_select_db("mydb",$db);
$result = mysql_query("SELECT * FROM employees",$db);
if ($myrow = mysql_fetch_array($result)) {
echo "<table border=1>\n";
echo "<tr><td>Name</td><td>Position</td></tr>\n";
do {
printf("<tr><td>%s %s</td><td>%s</tr>\n", $myrow["first"],
$myrow["last"], $myrow["address"]);
} while ($myrow = mysql_fetch_array($result));
echo "</table>\n";
} else {
echo "Sorry, no records were found!";
}
?>
</body>
</html>
-------------------------end of exam3-2a.php3----------------------
Take a look at this script.
<html>
<body>
<?php
$db = mysql_connect("localhost", "root");
mysql_select_db("mydb",$db);
$result = mysql_query("SELECT * FROM employees",$db);
if ($myrow = mysql_fetch_array($result)) {
echo "<table border=1>\n";
echo "<tr><td>Name</td><td>Position</td></tr>\n";
do {
printf("<tr><td>%s %s</td><td>%s</tr>\n", $myrow["first"],
$myrow["last"], $myrow["address"]);
} while ($myrow = mysql_fetch_array($result));
echo "</table>\n";
} else {
echo "Sorry, no records were found!";
}
?>
</body>
</html>
这个程序又引进了一些新特性,不过都很简单.首先是函数"mysql_fetch_array()",
它完全能实现"mysql_fetch_row()"的功能,不过多了一个非常好用的功能:我们
可以用它来用字段的名字来引用字段的内容(比如$myrow["first"]),而不是用数
字来引用,这帮我们解决了很多头疼的问题.前面我们已经介绍了do/while循环语
句和if-else条件判断语句的用法.
There are a number of new features introduced
here, but they're quite simple. First, there's the
mysql_fetch_array() function. This is exactly the
same as mysql_fetch_row() with one nice
exception: Using this function, we can refer to
fields by their names (such as $myrow["first"])
rather than their numbers. This should save us
some headaches. We've also introduced a do/while
loop and an if-else statement.
使用if-else语句,当我们可以将表格的某一行赋值给$myrow时,继续执行;否则,可以
跳转到相应的其他部分,再执行代码.
The if-else statement says that if we can assign a
row to $myrow, then continue; otherwise skip to
the else section and do what's in there.
do/while循环是while()循环的一个变种,我们在上一小节中用到过.这里我们有一个
很好的理由要使用do/while循环:在if语句的初始化过程中,我们将返回的查询结果的
第一行数据赋值给变量$myrow,这时我们执行的是的一般while语句的功能(就像,
while ($myrow = mysql_fetch_row($result)),如果第一行纪录无法存储到变量中,
我们就无法执行do/while内部的语句.do/while循环语句让我们可以测试条件,当那段
代码已经运行过之后.因此,这将不会因为其它的原因而忽略一行数据.
The do/while loop is a variation of the while() loop
we used on the last page. We need the do/while
loop here for a very good reason: With the initial if
statement, we assigned the first row returned by
the query to the variable $myrow. If at this point
we executed a regular while statement (such as
while ($myrow = mysql_fetch_row($result)), we'd
be kicking the first record out of the variable and
replacing it with the second record. But the
do/while loop lets us test the condition after the
code has been run once. So there's no chance of us
accidentally skipping a row.
最后,如果没有返回任何纪录,包含在else{}中的那部分代码将会执行,要想看到这部分
代码的执行动作,只要将SQL条件改成"SELECT * FROM employees WHERE id=6"或者其
它不会返回任何数据的SQL语句就行了.
Finally, if there are no records returned at all, the
statements contained in the else{} portion will be
executed. To see this portion in action, change the
SQL statement to SELECT * FROM employees
WHERE id=6 or something else that will return no
records.
现在,如果你开始喜欢上它的话,让我们再来对循环语句和if-else判断语句代码做
一些扩展,以生成一个更特别的页面.
Now let's extend this looping and if-else code to
make one fancy-schmancy page. You're going to
love it.
next page?
[未完待续]
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※ 来源:·紫 丁 香 bbs.hit.edu.cn·[FROM: ustsu54-nc2.ust]