PHP-and-MySQL - Data retrieval from Database

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Data retrieval from Database

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Can anyone tell me how the search function is done in websites??? i.e Some websites provide online dictionary, I think they use database like MySQL , to store words and meanings in tables , if a user enters a word in browser and hits "search" the corresponding word appears with meaning , how the "search function" above is done??? do they use any algorithm ? or simply storing and retrieving using the function like mysql_fetch_array()????

I messed up in this please help me to get cleared!

PHP-and-MySQL MySQL-Part-2 None min None sec 19-02-14, 9:26 p.m. Velu.N

Answers:

Hi Velu,

Consider you have a simple MySQL table named "dictionary" with the following structure and some entries.

------------------------------------------

Column | Type

------------------------------------------

word | varchar(200)

meaning | text

------------------------------------------

Now create a search.phpfile with the following content.

<!DOCTYPE html>

<head>

<title>Search</title>

</head>

<body>

<h3>Please enter your search term.</h3>

</form>

<?php

/* check if the method is POST */

if($_SERVER["REQUEST_METHOD"] === "POST") {

$term = $_POST["term"];

/* create a mysql connection */

$connection = mysql_connect("localhost", "username", "password");

if(!$connection) {

die("Database connection failed" . mysql_error());

}

/* select a mysql database */

$mysql_select = mysql_select_db("database_name", $connection);

if(!$mysql_select) {

die("Database selection failed" . mysql_error());

}

/* use the mysql query with LIKE clause */

$result = mysql_query(

"SELECT word, meaning FROM dictionary WHERE word LIKE '%{$term}%'", $connection

);

/* displaying results if any */

echo "Your search term = " . $term . " ";

echo "<h3>Results:</h3>" . "<hr>";

while($row = mysql_fetch_array($result)) {

echo "Word = " . $row["word"] . " ";

echo "Meaning = " . $row["meaning"] . " ";

echo "<hr>";

}

?>

</body>

</html>

Output:

Note (! Important):

1) change the username, password, and database_name to match your settings.

2) if you want exact term search, you can replace '%{$term}%'to '{$term}' in the query.

3) custom algorithms/ filters can be implemented on the retrieved data, in the above example inside the while loop.

4) in case you are in a doubt where to put the above submit.phpfile.

4.a) In GNU/Linux, please install apache2 web-server, and php5.

I hope you already have mysql installed by now.

Put the submit.php in /var/www/folder. (Grant it required permissions.)

4.b) In Macintosh, install <a href="http://www.mamp.info/en/index.html" target="_blank" title="MAMP">MAMP</a>,

Its default serving directory will be /Applications/MAMP/htdocs.

4.c) In Windoze install <a href="http://www.wampserver.com/en/" target="_blank" title="WAMP">WAMP</a>.

Its default serving directory will be c:\\wamp\\www.

Thanks,

Jayaram

20-02-14, 1:17 a.m. pai

Thank you sir,

Actually I am using XAMPP server in windows 7 OS. But before that I tried php in BOSS GNU/LINUX (this linux is provided with the Government Laptops for school and college students ,by Govt. of Tamil Nadu). I installed all the packages Apache, php-common ,php5..... etc, before that I installed MySQL packages which is running on 127.0.0.1 (localhost) .

Problem is , when I saved my sample.php file like,

</body>

</html>

and opened in browser, instead of opening as web page , the sample.php is downloaded and automatically stored in Downloads directory.(I tried many times with different php code but doesn,t work!)

Finally, I wanted to clarify whether my apache is working? so in Terminal I typed a command

<code>/etc/init.d/apache2 stop </code>

<code>/etc/init.d/apache2 start and found an error message </code>

<code>"could not successfully generate fully qualified domain name for 127.0.0.0,</code>

<code>port 80 is used by some other process"</code>

<code>

I assumed myself that the MySQL which I previously installed is using this port and running on 127.0.0.1.

I was unable to solve this and totally gave up!!!!

I think u can understand the problem if so please help me I like working with LINUX , I will be happy if this is solved!

please help me!

</code>

20-02-14, 10:11 p.m. Velu.N

Hi again,

First check whether the package libapache2-mod-php5 is installed in BOSS Linux.

Command to run in terminal ( to check whether package is installed ):

dpkg -s libapache2-mod-php5

If it is not installed, you might get an output somewhat similar like this:

----------------------------------------------------------------------------------

Package `libapache2-mod-php5' is not installed and no info is available.

Use dpkg --info (= dpkg-deb --info) to examine archive files,

and dpkg --contents (= dpkg-deb --contents) to list their contents.

----------------------------------------------------------------------------------

Now install libapache2-mod-php5:

Command:

apt-get install libapache2-mod-php5

After installation restart your apache2 web server:

Command:

/etc/init.d/apache2 restart

Note:

1) You need to have required permissions to install packages.

2) Since BOSS is Debain based Operating System, you can easily google your issues as if you are using a Debian OS.

You will get better results since the Debian community is larger than BOSS.

Let me know the if you need any more help.

Thanks.

21-02-14, 3:19 a.m. pai

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