PHP methods to implement five basic operations on text database_PHP tutorial

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PHP实现对文本数据库的数据显示、加入、修改、删除、查询五大基本操作的方法
我用一个留言本程序作为例子，阐述PHP实现对文本数据库的数据显示、加入、修改、删除、查询五大基本操作的方法。
此文本数据库共有字段10个：客户IP、发言时间、客户名、客户EMAIL、客户主页地址、留言表情图片名、客户QQ、客户形象图片、留言内容、管理员回复内容。

1、加入数据程序段。
$date=date("Y-m-d H:i:s");//取得系统时间
$ip = $HTTP_SERVER_VARS[REMOTE_ADDR]; //取得发言的IP地址
$text=encode($gb_text);//去掉留言内容后面的空格.
$fp=fopen("gb.dat","a");//以只写模式打开gb.dat文本文件,文件指针指向文件尾部.
$str=$ip."|".$date."|".$gb_name."|".$gb_email."|".$gb_home."|".$face."|".$gb_qq."|".$head."|".$text."|".$reply." ";//将所有留言的数据赋予变量$str，"|"的目的是用来今后作数据分割时的数据间隔符号。
fwrite($fp,$str);//将数据写入文件
fclose($fp);//关闭文件
showmessage("留言成功!","index.php","3");//留言成功，3秒后自动返回主界面。
其中的$gb_name 、$gb_email、$gb_home、$face、$gb_qq、$head、$gb_text、$reply是由发言表单传过来的数据。

2、数据显示程序段
if (file_exists("gb.dat")){//检测文件是否存在
$array=file("gb.dat");//将文件全部内容读入到数组$array
$arr=array_reverse($array);//将$array里的数据安行翻转排列（即最后一行当第一行，依此类推）读入数组$arr的每一个单元（$arr[0]...）。
$num=count($array);//获取数组$array里的信息数(一行为一条信息)
if ($num>0){//如果信息数大于零（即文本数据库不为空）
$total=ceil($num/$pagesize);//计算总页数(取最大整数,即凡有小数点都进一取整，$pagesize为预设的每页显示的信息数)
if($page<1){//如果当前页面数码号小于1
$page=1;//则赋值为1
}
$number=($page-1)*$pagesize;//计算当前所显示第一个留言的数码号（数码号从零开始，主要是达到与数组单元号对应的目的）
for($i=0;$i<=$pagesize-1;$i++){//进入循环
$row=explode("|",$arr[$number]);//以"|"作为分割符,分割数组$arr中每第$number个单元的数据,并将这些数据赋予数组$rom
list($ip,$datetime,$name,$email,$home,$face,$qq,$head,$text,$reply)=$row;//将数组$row里的单元数据按顺序赋予括号里的变量
?>
>//显示客户形象图片


昵称【】
//显示客户名
发表于：//显示留言发表时间


>//显示客户留言表情图片
说://显示客户留言内容


//显示回复内容


访问的主页//客户主页的超连接
给发信//客户E-MAIL的连接
的QQ号码是//显示客户的QQ号码
的IP地址为" //显示客户的IP地址
回复//留言回复的连接语句
删除//留言删除的语句（以客户留言时间$datetime作为删除标识）


if ($number == $num-1)//如果数组的单元号等于总留言数减一（因为单元号以零开始的，所以这意味着这是最后一条留言）
{
break;//跳出循环
}
$number = $number + 1; //数组单元号加1
}//循环结束符
}
if ($page <> 1)//如果当前页面数码号不等于1
{
$back = $page - 1;//当前页面数码号减1，并将此值赋予变量$back
echo "第一页";//显示第一页的连接
echo " 上一页" ;当前页面数码号等于$back，并显示其连接
}
if ($page <> $total)//如果当前页面数码号不等于总页数号（最后一页数码号）
{
$next = $page + 1;//当前页面数码号加1并赋予变量$next
echo " 下一页" ;//显示下一页连接
echo " 最后一页"; 显示最后一页连接
}
echo "页数：$page / $total";//显示当前页面数码号和显示最后一页数码号
echo "共有 $num 条留言";//显示留言数信息

}
else {
echo "

当前没有任何留言！";//如果文件内容为空则显示的信息
}
else {
echo "数据文件丢失，请联系管理员！或发布留言重新建立数据文件！";//如果文件不存在显示的信息
}

3. Data modification program segment
$list=file("gb.dat");//Read the entire gb.dat file into the array $list, each element of the array is a message ($list[0 ] is the data of the first message, $list[1] is the data of the first message....
$n=count($list);//Calculate the total number of messages in the $list content, and Assign the variable $n
if ($n>0){ //If the number of messages is greater than 0
$fp=fopen("gb.dat","w");//Open the file in write-only mode gb.dat
$gb_reply=encode($gb_reply);
for ($i=0;$i<$n;$i++) {//Enter the loop
if(eregi($ttime,$ list[$i])){//Compare the string matching time $ttime sent to send a message with the content in the array unit $list
$f=explode("|",$list[$i]); //If a match is found, use "|" as the delimiter to cut the message information $list[$i] (the $ith message), and assign these data to the array $f
$f[9]= $gb_reply;//Replace $f[9] (the last piece of data in the message) with $gb_reply (reply content)
$list[$i]=$f[0]."|".$f[. 1]."|".$f[2]."|".$f[3]."|".$f[4]."|".$f[5]."|".$f[ 6]."|".$f[7]."|".$f[8]."|".$f[9]." "; //Replace the contents of the array unit $list[$i] with the array $f plus the separator "|" (where $f[9] is the modified new data).
break; // Jump out Loop
}
}//Loop end character
}
FOR($i=0;$i<=$n;$i++){//Enter loop
fwrite($fp ,$list[$i]);//Create each unit of the array $list into one line and write it to the file gb.dat
}//Loop end character
fclose($fp);//Close the file
showmessage("Reply successfully!","index.php");//Reply successfully and automatically return to the main interface

4. Data deletion program segment
$list=file("gb.dat");//Read the entire gb.dat file into the array $list, each element of the array is a message ($list[0 ] is the data of the first message, $list[1] is the data of the first message....
$n=count($list);//Calculate the total number of messages in the $list content, and Assign the variable $n
if ($n>0){//If the number of messages is greater than 0
$fp=fopen("gb.dat","w");//Open the file in write-only mode gb.dat
for ($i=0;$i<$n;$i++) {//Enter the loop
if(eregi($ttime,$list[$i])){//Will send Come and send a message. The time $ttime is matched with the strings in the array $list[$i]
$list[$i]="";//If the match is successful, $list[$i] will be cleared ( To achieve the purpose of deletion)
break;//Jump out of the loop
}
}//Loop end character
FOR($i=0;$i<=$n;$i++){// Enter the loop
fwrite($fp,$list[$i]);//Convert each unit of the array $list into a line and write it to the file gb.dat
} //Loop end character
fclose ($fp);//Close the file
showmessage("Delete successfully!","index.php");//Delete successfully and automatically return to the main interface.
}

5. Data query program segment

/////////////////////// //////////The above is the search form statement segment
$id=0;
$list=file("gb.dat");//Read the entire gb.dat file to the array $list, each element of the array is a message ($list[0] is the data of the first message, $list[1] is the data of the first message....
$n=count($list);//Calculate the total number of messages in the $list content and assign it to the variable $n
$found=trim($found);
if (!$found){ //If $found is false
echo "You did not enter any keywords!";//For related display
}
else {
if($n>0 ){//If the number of messages is greater than 0
for ($i=0;$i<$n;$i++) {//Enter the loop
if(eregi($found,$list[$i]) ){//The entered keywords are matched and compared with the strings in the array $list[$i]
$row=explode("|",$list[$i]); $id=1; // If a match is found, use "|" as the delimiter to cut the message information $list[$i] (the $ith message), and assign these data to the array $row. And assign 1 to the variable $id so as to Determine whether a match is found.
list($ip,$datetime,$name,$email,$home,$face,$qq,$head,$text,$reply)=$row;//Change the array $ The unit data in the row is assigned to the variables in the brackets in order
?>
>//Display the customer image picture


Nickname【】
//Display customer name
Posted in ：//Display the message publishing time


>//Display the customer message emoticon picture
Say://Show customer

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