PHP新手上路(十一)
author:一佰互联 2019-05-01   click:139
数据库链接 10. PHP最大的特色就是操作数据库的能力特别的强大,PHP提供对多种数据库的支持。   通过PHP你可以轻松的连接到数据库,请求数据并将其显示在你的web站点中,甚至修改数据库中的数据。在这一节里我们主要以在互联网上跟PHP一起使用得最多的MySQL数据库为例,介绍一下相关的MySQL数据库的操作函数以及数据库的基本操作等方面的知识。 在MySQL数据库中,我们用来连接数据库的函数有两个,它们分别为: integer mysql_connect(string host,string user,string password); integer mysql_pconnect(string host,string user,string password); mysql_connect函数和mysql_pconnect函数都是对指定主机上MySQL数据库的连接,如果该数据库位于一个不同的端口,则可以在主机名后加上冒号和端口号。函数的参数也可以缺省不填,如果不填参数,默认的主机名是“localhost”,用户名为数据库管理员,默认值为“root”,密码为空。与数据库连接成功之后,这两个函数都可以返回一个连接号,如果连接失败,则返回一个false值。让我们来看看下面几句语句: <? $db=mysql_connect("localhost","user","password"); mysql_select_db("mydb",$db); ?> 注释: $db=mysql_connect("localhost","user","password"); 我们将mysql的链接参数,包括主机名、用户名和密码作为mysql_connect()的参数,同时得到返回值为$db,这样,在下面的语句中,我们就可以将变量$db作为一个连接mysql数据库的连接号来使用。 mysql_select_db("mydb",$db); 将PHP程序链接到mydb数据库中,这样程序与数据库的链接就完成了。 10.1 一个简易的数据库留言簿   在完成数据库的链接之后,我们就可以对数据库进行一系列的操作。下面是一个简易的数据库留言簿程序(guestbook.php3):   我假设你机子上的MySQL数据库以及管理MYSQL数据库的工具 Phpmyadmin_2. 0.5都已经安装完成,并且可以正常工作。 我们要做的第一件事情是创建一个留言数据库,假定名字为: mydb。 1、启动浏览器,打开Phpmyadmin_2. 0.5 的管理WEB界面。 2、在“Create new database”文本框内输入数据库名称mydb,然后按create按键。   下一步,我们要在该留言数据库下创建一个数据表,假定名字为: guestbook。 创建该数据表的命令如下所示:  CREATE TABLE guestbook (ID INT NOT NULL AUTO_INCREMENT, name CHAR(250), email CHAR(250), job CHAR(250), comments BLOB, PRIMARY KEY(ID));  最后,将下面的留言簿程序挎贝到你机子的可写目录下面,并保存成guestbook.php3文件。就这么简单,你已经有了自己的留言簿了。  10.2 留言簿程序(guestbook.php3): <?php  /* $host : your MySQL-host, usually "localhost" */ /* $user : your MYSQL-username */ /* $password : your MySQL-password */ /* $database : your MySQL-database */ /* $table : your MySQL-table */ /* $page_title : the title of your guestbook-pages */ /* $admin_mail : email-address of the administrator to send the new entries to */ /* $admin_name : the name of the administrator */ /* $html_mail : say yes if your mail-agent can handle HTML-mail, else say no */ $host = "localhost"; $user = ""; $password = ""; $database = "mydb"; $table = "guestbook"; $page_title = "pert guestbook"; $admin_mail = "pert@21cn.com"; $admin_name = "Webmaster"; $html_mail = "no"; ?> <HTML> <HEAD> <TITLE><?php echo $page_title; ?></TITLE> </HEAD> <BODY BGCOLOR="#FFFFFF" LINK="#000000"> <FONT FACE="Verdana" SIZE="-2"> <? /* connect to the database */ mysql_pconnect("$host","$user","$password") or die("Can"t connect to the SQL-server"); mysql_select_db("$database"); /* action=view : retrieve data from the database and show it to the user */ if($action == "view") { /* function for showing the data */ function search_it($name) { /* some vars */ global $offset,$total,$lpp,$dir; global $table,$html_mail,$admin_name,$admin_mail; /* select the data to get out of the database */ $query = "SELECT name, email, job, comments FROM $table"; $result = mysql_query($query); $total= mysql_numrows($result); print "<CENTER><FONT FACE="Verdana" SIZE="-2"><A HREF="guestbook.php3?action=add" onMouseOver="window.status="Add your name";return true" onMouseOut="window.status="";return true" TITLE="Add your name">加入留言</A></FONT></CENTER><br><br>"; if ($total== 0) { print "<CENTER>此刻没人留言</CENTER><br><br>"; } elseif ($total> 0) { /* default */ $counter=0; if ($dir=="") $dir="Next"; $lpp=5; if ($offset==0) $offset=0; if ($dir=="Next") { if ($total > $lpp) { $counter=$offset; $offset+=$lpp; $num=$offset; if ($num > $total) { $num=$total; } } else { $num=$total; } } elseif ($dir=="Previous") { if ($total > $lpp) { $offset-=$lpp; if ($offset < 0) { $offset=0; } $counter=$offset-$lpp; if ($counter < 0) $counter=0; $num=$counter+$lpp; } else { $num=$total; } } while ($counter < $num) { $j=0; $j=$counter + 1; /* now really grab the data */ $i1=mysql_result($result,$counter,"name"); $i2=mysql_result($result,$counter,"email"); $i3=mysql_result($result,$counter,"job"); $i4=mysql_result($result,$counter,"comments"); $i4 = stripslashes ("$i4"); /* print it in a nice layout */ print "<CENTER>n"; print "<TABLE WIDTH=400 BORDER=0 ALIGN=CENTER VALIGN=TOP><TR><TD><FONT FACE="Verdana" SIZE="-2">n"; print "<HR>n"; print "<BR><B>Name:</B> $i1n"; print "<BR><B>email:</B><A HREF="mailto:$i2" onMouseOver="window.status="Email $i2";return true" onMouseOut="window.status="";return true" TITLE="Email $i2">$i2</A>n"; print "<BR><B>Job:</B> $i3n"; print "<BR><B>Comment:</B>n"; print "<BR>$i4n"; print "</FONT></TD></TR></TABLE>n"; print "</CENTER>n"; $counter++; } } mysql_close(); } /* execute the function */ search_it($name); /* See if we need to put on the NEXT or PREVIOUS buttons */ if ($total > $lpp) { echo("<form action="$PHP_SCRIPT" method="POST">n"); /* See if we need a PREVIOUS button */ if ($offset > $lpp) { echo("<input type="submit" value="Previous" name=dir>n"); } /* See if we need a NEXT button */ if ($offset < $total) { echo("<input type="submit" value="Next" name=dir>n"); } echo("<input type=hidden name="offset" value="$offset">n"); echo("<input type=hidden name="name" value="$name">n"); echo("</form>"); } } /* action=add : show a form where the user can enter data to add to the database */ elseif($action == "add") { ?> <TABLE WIDTH="460" ALIGN="CENTER" VALIGN="TOP"> <TH COLSPAN="2"><P>请您填写留言</TH> <FORM NAME="guestbook" ACTION="guestbook.php3?action=send" METHOD="POST"> <TR> <TD ALIGN="RIGHT" VALIGN="TOP"> 您的大名:</TD> <TD><INPUT TYPE=text NAME=name></TD> </TR> <TR> <TD ALIGN="RIGHT" VALIGN="TOP"> 您的E-mail:</TD> <TD> <INPUT TYPE=text NAME=email></TD> </TR> <TR> <TD ALIGN="RIGHT" VALIGN="TOP"> 您的工作:</TD> <TD> <INPUT TYPE=text NAME=job></TD> </TR> <TR> <TD ALIGN="RIGHT" VALIGN="TOP"> 您的留言:</TD> <TD> <TEXTAREA NAME=comments COLS=40 ROWS=6></TEXTAREA> <P> <INPUT TYPE=submit VALUE=Submit> <INPUT TYPE=Reset VALUE=Reset>  <A ALIGN="RIGHT" HREF="guestbook.php3?action=view" onMouseOver="window.status="Read all comments first";return true" onMouseOut="window.status="";return true" TITLE="Read all comments first"><FONT SIZE="-2">先观看所有的留言</FONT></A> </TD> </TR> </FORM> </TABLE> </CENTER> <? } /* action=send : add the data from the user into the database */ elseif($action == "send") { /* check if a HTML-mail should be send or a plain/text mail */ if($html_mail == "yes") { mail("$admin_name <$admin_mail>","PHP3 Guestbook Addition","<HTML><BODY><FONT FACE="Century Gothic"><TABLE BORDER="0" WIDTH="100%" CELLSPACING="4"><TR>$name ($email) schreef het volgende bericht in het gastenboek :</TR><TR><TD ALIGN="LEFT"> </TD><TD ALIGN="LEFT" NOWRAP> </TD></TR><TR><TD ALIGN="LEFT">$comments</TD><TD ALIGN="LEFT" NOWRAP> </TD></TR><TR><TD ALIGN="LEFT"> </TD><TD ALIGN="LEFT" NOWRAP> </TD></TR><TR><TD ALIGN="LEFT">您的留言:</TD><TD ALIGN="LEFT" NOWRAP>$name</TD></TR><TR><TD ALIGN="LEFT">您的大名:</TD><TD ALIGN="LEFT" NOWRAP>$email</TD></TR><TR><TD ALIGN="LEFT">您的email:</TD><TD ALIGN="LEFT" NOWRAP>$job</TD></TR><TR><TD ALIGN="LEFT">您的工作:</TD></TR></TABLE></BODY></FONT></HTML>", "From: $name <$email>nReply-To: $name <$email>nContent-type: text/htmlnX-Mailer: PHP/" . phpversion()); } /* MySQL really hates it when you try to put things with " or " characters into a database, so strip these...*/ $comments = addslashes ("$comments"); $query = "INSERT INTO guestbook VALUES("","$name", "$email", "$job", "$comments")"; $result = MYSQL_QUERY($query); ?> <BR><P ALIGN = CENTER>感谢, <?php echo $name; ?>, 您的留言. <BR><P ALIGN = CENTER><A HREF="guestbook.php3?action=view" onMouseOver="window.status="View your comment now";return true" onMouseOut="window.status="";return true" TITLE="View your comment now">观看留言</A><BR><BR> <? } /* if there"s no action given, then we must show the main page */ else { /* get the number of entries written into the guestbook*/ $query = "SELECT name from guestbook"; $result = MYSQL_QUERY($query); $number = MYSQL_NUMROWS($result); if ($number == "") { $entry = "还没有人留过言"; } elseif ($number == "1") { $entry = "目前留言人数1人"; } else { $entry = "目前留言人数 $number 人"; } echo "<CENTER><BR>"; echo "<P>$entry<BR>"; echo "<H4><FONT FACE="Verdana" SIZE="3"><A HREF="guestbook.php3?action=add" onMouseOver="window.status="请您留言";return true" onMouseOut="window.status="";return true" TITLE="Add your name to our guestbook">请您留言</A></FONT></H4>"; if ($number > "") { echo "<H4><FONT FACE="Verdana" SIZE="3"><A HREF="guestbook.php3?action=view" onMouseOver="window.status="观看留言";return true" onMouseOut="window.status="";return true" TITLE="View the names in our guestbook">观看留言</A></FONT></H4>"; } echo "</P></CENTER>"; } ?> <BR><SMALL><CENTER>版权所有:<A HREF="http://personal.668.cc/haitang/index.htm" onMouseOver="window.status="pert";return true" onMouseOut="window.status="";return true" TITLE="pert">无边天际</A></CENTER></SMALL> </FONT> </BODY> </HTML>