<?php // RAY_mysql_example.php
error_reporting(E_ALL);
// IMPORTANT PAGES FROM THE MANUALS
// MAN PAGE: http://us2.php.net/manual/en/ref.mysql.php
// MAN PAGE: http://us2.php.net/manual/en/mysql.installation.php
// MAN PAGE: http://us.php.net/manual/en/function.mysql-error.php
// CONNECTION AND SELECTION VARIABLES FOR THE DATABASE
$db_host = "localhost"; // PROBABLY THIS IS OK
$db_name = "??"; // GET THESE FROM YOUR HOSTING COMPANY
$db_user = "??";
$db_word = "??";
// OPEN A CONNECTION TO THE DATA BASE SERVER
// MAN PAGE: http://us2.php.net/manual/en/function.mysql-connect.php
if (!$db_connection = mysql_connect("$db_host", "$db_user", "$db_word"))
{
$errmsg = mysql_errno() . ' ' . mysql_error();
echo "<br/>NO DB CONNECTION: ";
echo "<br/> $errmsg <br/>";
}
// SELECT THE MYSQL DATA BASE
// MAN PAGE: http://us2.php.net/manual/en/function.mysql-select-db.php
if (!$db_sel = mysql_select_db($db_name, $db_connection))
{
$errmsg = mysql_errno() . ' ' . mysql_error();
echo "<br/>NO DB SELECTION: ";
echo "<br/> $errmsg <br/>";
die('NO DATA BASE');
}
// IF WE GOT THIS FAR WE CAN DO QUERIES
// ESCAPING A DATA FIELD FOR USE IN MYSQL QUERIES
// MAN PAGE: http://us2.php.net/manual/en/function.mysql-real-escape-string.php
$safe_username = mysql_real_escape_string($_POST["username"]);
// CREATING AND SENDING A SELECT QUERY AND TESTING THE RESULTS
// MAN PAGE:http://us2.php.net/manual/en/function.mysql-query.php
$sql = "SELECT id FROM my_table WHERE username='$safe_username'";
$res = mysql_query($sql);
// IF mysql_query() RETURNS FALSE, GET THE ERROR REASONS
// MAN PAGE: http://us.php.net/manual/en/function.mysql-error.php
if (!$res)
{
$errmsg = mysql_errno() . ' ' . mysql_error();
echo "<br/>QUERY FAIL: ";
echo "<br/>$sql <br/>";
die($errmsg);
}
// IF WE GET THIS FAR, THE QUERY SUCCEEDED AND WE HAVE A RESOURCE-ID IN $res SO WE CAN NOW USE $res IN OTHER MYSQL FUNCTIONS
// DETERMINE HOW MANY ROWS OF RESULTS WE GOT
// MAN PAGE: http://us2.php.net/manual/en/function.mysql-num-rows.php
$num = mysql_num_rows($res);
if (!$num)
{
echo "<br/>QUERY FOUND NO DATA: ";
echo "<br/>$sql <br/>";
}
else
{
echo "<br/>QUERY FOUND $num ROWS OF DATA ";
echo "<br/>$sql <br/>";
}
// ITERATE OVER THE RESULTS SET TO SHOW WHAT WE FOUND
// MAN PAGE: http://us2.php.net/manual/en/function.mysql-fetch-assoc.php
echo "<pre>\n"; // MAKE IT EASY TO READ
while ($row = mysql_fetch_assoc($res))
{
var_dump($row); // MAN PAGE: http://us2.php.net/manual/en/function.var-dump.php
}
// A WAY OF DETERMINING HOW MANY ROWS WE HAVE IN A TABLE
// MAN PAGE: http://us.php.net/mysql_fetch_array
$sql = "SELECT COUNT(*) FROM my_table";
$res = mysql_query($sql);
// IF mysql_query() RETURNS FALSE, GET THE ERROR REASONS
if (!$res)
{
$errmsg = mysql_errno() . ' ' . mysql_error();
echo "<br/>QUERY FAIL: ";
echo "<br/>$sql <br/>";
die($errmsg);
}
// GET THE RESULTS SET ROW IN AN ARRAY WITH A NUMERIC INDEX - POSITION ZERO IS THE COUNT
$row = mysql_fetch_array($res, MYSQL_NUM);
$num = $row[0];
// MAKING AN INSERT QUERY AND TESTING THE RESULTS
$sql = "INSERT INTO my_table (username) VALUES (\"$safe_username\")";
$res = mysql_query($sql);
// IF mysql_query() RETURNS FALSE, GET THE ERROR REASONS
if (!$res)
{
$errmsg = mysql_errno() . ' ' . mysql_error();
echo "<br/>QUERY FAIL: ";
echo "<br/>$sql <br/>";
die($errmsg);
}
// GET THE AUTO_INCREMENT ID OF THE RECORD JUST INSERTED - PER THE DB CONNECTION
// MAN PAGE: http://us2.php.net/manual/en/function.mysql-insert-id.php
$id = mysql_insert_id($db_connection);
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