I got sick of coming across classes that didn’t have everything I needed, or didn’t do it correctly. One of my biggest problems was an inability to nest query calls within another query result’s output.

Example:

<?php

// main query
// gets a list of companies from the companies table
$a = "SELECT id, company_name FROM companies";
$a = $db->query($a);

while  ($aa = $db->fetch_object($a) ) :

     echo '<div class="company_name">' . $aa->company_name . '</div>';

     // get the contacts for each company
     $b = "SELECT contact_name, phone1 FROM contacts WHERE company_id = $aa->id"; // because we've already used $a, we can't use it again during $a's output
     $b = $db->query($b);

     // output all contacts for the each company
     while ( $bb = $db->fetch_object($b) ) : // the same thing as $a, we can not use $aa again during its output
          echo '<div class="contact_name">' . $bb->contact_name . '</div>';
          echo '<div class="contact_phone">' . $bb->phone1 . '</div>';
     endwhile;

endwhile;

?>

With this class, that is not a problem. The only requirement is that you can’t name your $sql and $results ($row) variables the same (noted in the code above). Other than that, there’s nothing to it. It’s just a way to provide clean, and efficient database interaction.

Database Class Code

• Updated 02-10-2012:

  • Renamed database class to Framework_Database to signify this class is a framework level class.
  • Most everything was re-written to tighten up the code.
  • Moved the database connection settings to a $config object. Allows for a single configuration file of your choosing.
  • Got rid of error_backtracing() and show_mysql_error() since it didn’t really work. It will now print the error to screen, via $db->error() (called automatically), if $config->errors['display'] is set to true. If false, it will email the error to $config->errors['email_to'].

Despite the re-write, your $db->query(), $db->fetch_object(), etc. methods are still there and still work the same.

<?php
if ( !isset($config) ) :
	# ###
	#
	$config = (object) array();
		#
		# database connection settings
		$config->db = array(
			'host'                => '',
			'user'                => '',
			'password'            => '',
			'db_name'             => ''
		);

		#
		# error display settings
		$config->errors = array(
			'display'     => true,
			'redirect_to' => '/error',
			'email_to'    => 'email@yourdomain.com',
			'email_from'  => 'email@yourdomain.com',
			'style_sheet' => 'css/error-reports.css',
			'suppressed_error_message' => '<div align="center"><b style="font-size: 150%;">an error has occurred and email has been sent the administrator</b></div>'
		);
	#
endif;

/* **********************************************************************
*	Framework_Database is a class created to manage database functions
*
*
*	The class manages all database interraction for the purpose of allowing certain things to be
*	turned on and off, as well as making development easier and more uniform.
*   An example would be Error Reporting.  Once the application is on the live
*	server, we can set $config->errors['display'] to false. Error reporting for database erros will not be shown.
*
*	This is real simple to use
*
*
*
*
******************************
**
**
**
**
**	Configuration ***
**		Scroll to the __construct method if you need to change which object
**		the database class uses for $config->connection and $config->errors
**
**
**
**
******************************
*
*	Examples:
*
********************
*
*		Get number of rows returned in a query (you can also nest this:
*			$sql = "SELECT fieldA, fieldB FROM tableA"; // would return 4 rows
*			$sql = $db->query($sql);
*			$rows = $db->num_rows();
*			echo $rows; // 4
*
*		Nested num_rows();
*			$a = "SELECT fieldA FROM tableA"; // would return 2 rows
*			$a = $db->query($a);
*			$a = $db->fetch_object($a);
*			$a_rows = $db->num_rows();
*			echo $a_rows; // 2
*
*			while ($a_row = $db->fetch_object($a) ) :
*				$b = "SELECT fieldA FROM tableA WHERE fieldA = {$a_row->fieldA}"; // would return 6 rows
*				$b = $db->fetch_object($b);
*				$b_rows = $db->num_rows();
*					echo $b_rows; // 6
*				while ( $b_row = $db->fetch_object($b)) :
*					echo $b_row->fieldA;
*				endwhile;
*			endwhile;
*
*
********************
*
*
*		Results as Object:
*			$sql = "SELECT fieldA, fieldB FROM tableA";
*			$sql = $db->query($sql);
*
*			while ($row = $db->fetch_object($sql) ) :
*				echo $row->fieldA . ': ' . $row->fieldB;
*			endwhile;
*
*
********************
*
*
*		Results as Array:
*			$sql = "SELECT fieldA, fieldB FROM tableA";
*			$sql = $db->query($sql);
*
*			while ($row = $db->fetch_array($sql) ) :
*				echo $row['fieldA'] . ': ' . $row['fieldB'];
*			endwhile;
*
*
********************
*
*
*		Return value of a row or field in a row
*		( uses the mysql_result() method rather than the more inefficient mysql_fetch_row() )
*
*		Specify the field's position in the Result Set
*			$sql = "SELECT fieldA, fieldB FROM tableA";
*			$val = $db->fetch_row(1);        // would return fieldB's value
*
*		Specify the field name specifically
*			$val = $db->fetch_row('fieldA'); // would obviously return fieldA's value
*
*
********************
*
*
*		Return value of a query more efficiently (avoids the inefficient mysql_fetch_row() function)
*			$sql = "SELECT fieldA FROM tableA";
*			$fieldA = $db->fetch_value($sql); // would return fieldA's value
*
*
********************
*
*
*		 Return the query result set as an array:
*			$sql = "SELECT fieldA, fieldB FROM tableA"; // returns 4 rows
*			$results = $db->to_array($sql);
*
*			$results[0]['fieldA'] = 'valueA 1';
*			$results[0]['fieldB'] = 'valueB 1';
*
*			$results[1]['fieldA'] = 'valueA 2';
*			$results[1]['fieldB'] = 'valueB 2';
*
*			$results[2]['fieldA'] = 'valueA 3';
*			$results[2]['fieldB'] = 'valueB 3';
*
*			$results[3]['fieldA'] = 'valueA 4';
*			$results[3]['fieldB'] = 'valueB 4';
*
* 		Example with foreach loop:
*			foreach ($results as $key=>$result) :
*				echo $result['fieldA'].'<br />'.$results['fieldB'];
*			endforeach;
*
*
********************************************************************** */

class Framework_Database {

	# set whether errors should be displayed or not
	# probably want to turn off once site is live
	var $connect_type  = 'mysql';
	var $sql_txt       = '';
	var $config;

	/* ****************************************************************
	*
	* __construct
	*
	**************************************************************** */
	function __construct() {
		$this->config = (object) array();

		# ####
		#
		# $config object:
		# 	To make it easier to change which object is used for
		# 	connection and error configuration, we'll set it here
		#
		# Change $config to whatever is used for configuration settings
		#
			global $config;
			$this->config->errors = $config->errors;
			$this->config->db     = $config->db;
		# END
		#
		# ####
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Establish connection to the database
	* Be sure to set the connection info above
	*
	**************************************************************** */
	function connect() {
		global $config,$db;

			if ( !empty($config->db['db_name']) ) :

				#
				# try the connection
				$this->db_link = mysql_connect($config->db['host'], $config->db['user'], $config->db['password']);

				# The connection failed for some reason
				if ( !$this->db_link ) :
					die("Error connecting to the server");

				# The connection is good so lets get the Application Config Settings
				# and create the $config object
				else :
					$db_selected = mysql_select_db($config->db['db_name']);

				endif;

			endif;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Generates a random ID for the $sql object.
	* This allows nested query output
	*
	**************************************************************** */
	function sqlId() {
		$id = rand();
		$uniqueId[] = 'sql' . $id;
		$uniqueId[] = 'row' . $id;
		return $uniqueId;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Error
	* If @$config->errors['display'], print errors to screen
	* Else, we format the SQL and SQL error and email to
	*	$config->errors['email_to']
	*
	**************************************************************** */
	function error() {
		global $config, $__email;

		$display_error    = (bool) ( isset($config->errors['display']) && @$config->errors['display'] );
		$has_error        = (bool) ( isset($this->error) && !empty($this->error) );

		if ( @$display_error && @$has_error ) :
			echo $this->error;

		else :

			# ####
			#
			# Error has occurred
			# Send an email if Display errors is turned off
			#
			if ( @$has_error ) :

				$site_domain = preg_replace("/^(.*\.)?([^.]*\..*)$/", "$2", $_SERVER['HTTP_HOST']);
				# ####
				#
				# An error has occurred
				# Format the error email message so we can send it
				$vars['to']['email']   = $config->errors['email_to'];
				$vars['from']['email'] = 'no-reply@'.$site_domain;

				$vars['subject'] = 'Database Error Occurred ' . date('m-d-Y H:i:s');

				$sql_txt = nl2br($this->format_sql($this->sql_txt));
				$sql_txt = str_replace("\t",'&nbsp;&nbsp;', $sql_txt);

				$sql_err = nl2br($this->format_sql($this->error));
				$sql_err = str_replace("\t",'&nbsp;&nbsp;', $sql_err);

				$vars['message'] = "<p><strong>SQL Statement:</strong><br />"
								 . $sql_txt
								 . "</p>"
								 . "<p><strong>Error Text:</strong><br />"
								 . $sql_err
								 . "</p>";
				# END
				#
				# ####

				# ####
				#
				# Put together the email and send it
				$boundary = md5( uniqid ( rand() ) );

				$to_name    = (isset($vars['to']['name'])) ? $vars['to']['name'] : $vars['to']['email'];
				$to_email   = $vars['to']['email'];
				$from_name  = (isset($vars['from']['name'])) ? $vars['from']['name'] : $vars['from']['email'];
				$from_email = $vars['from']['email'];
				$replyto    = isset($vars['replyto']) ? $vars['replyto'] : $vars['from']['email'];
				$subject    = $vars['subject'];
				$message    = $vars['message'];

				$headers  = "From: ".$from_email."\n";
				if (!empty($replyto)) :
					$headers  .= "Reply-To: ".$replyto."\n";
				endif;
				$headers .= "Received: \"".$to_name."\" <".$to_email.">\n";
				$headers .= "MIME-Version: 1.0\n";
				$headers .= "Subject: ".$subject."\n";
				$headers .= "Content-Type: multipart/related;";
				$headers .= "boundary=\"------------".$boundary."\"\n";
				$headers .= "This is a multi-part message in MIME format.\n";
				$headers .= "--------------".$boundary."\n";
				$headers .= "Content-Type: text/html; charset=ISO-8859-1\n";
				$headers .= "Content-Transfer-Encoding: 7bit";

				mail($to_email, $subject, $message, $headers);
				# END
				#
				# ####
			endif;

		endif;
		$this->error='';
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Formats the SQL Statement. Hand for screen print
	* Mainly used for the error email, to make it more readable
	*
	**************************************************************** */
	function format_sql( $sql ) {

		$reserved_words = array(
			"/SELECT/",
			"/FROM/",
			"/WHERE/",
			"/CONCAT/",
			"/INNER /",
			"/ JOIN/",
			"/LEFT /",
			"/RIGHT /",
			"/MATCH/",
			"/AGAINST/",
			"/AND/",
			"/ORDER BY/",
			"/ OR /",
			"/ASC/",
			"/DESC/",
			"/LIMIT/",
			"/ IN /",
			"/SUM/",
			"/GROUP BY/",
			"/GROUP_/",
			"/SEPARATOR/"
		);

		$sql_err = '';
		$sql_txt = $sql;
		if ( strstr($sql, 'Query: ') ) :
			$sql = explode('Query: ', $sql);
			$sql_err = $sql[0];
			$sql_txt = $sql[1];
		endif;

		$sql_txt = preg_replace($reserved_words, "<span class=\"reserved_word\" style=\"color: #3f97c6!important; font-weight: bold!important;\">$0</span>", $sql_txt);
		return $sql_err.$sql_txt;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Run the query
	*
	**************************************************************** */
	function query( $sql='' ) {

		## keep the string value of the SQL statement in case of error
		$this->sql_txt = $sql;

		if ( $this->connect_type == 'mysql' ) :
			$this->result=mysql_query( $sql );

			if ( !$this->result ) :
				$this->error = mysql_error() . '<br />Query: '.$sql;
				$this->error();
				$this->result = false;
			endif;

		else :
			$result = mysqli_query( $this->db_link, $sql );
			$this->result = $result;

			if ( !$this->result ) :
				$this->error = mysqli_error($this->db_link) . '<br />Query: '.$sql;
				$this->error();
				$this->result = false;
			endif;

		endif;

		return $this->result;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Connect to the server using the mysqli extension
	* This is used automatically during multi_query()
	*
	**************************************************************** */
	function mySqliConnect() {
		global $config;
		$this->mySqli = new mysqli($config->db['host'], $config->db['user'], $config->db['password'], $config->db['db_name']);
		return $this->mySqli;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Close the mysqli connection once we have finished
	* using the multi_query() method
	*
	**************************************************************** */
	function mySqliClose() {
		mysqli_close($this->mySqli);
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Execture the multi-query
	*
	**************************************************************** */
	function multi_query( $sql='' ) {

		## keep the string value of the SQL statement in case of error
		$this->sql_txt = $sql;

		$mysqli = $this->mySqliConnect();

		$this->result = mysqli_multi_query( $mysqli, $sql );

		if ( !$this->result ) :
			$this->error = mysql_error() . '<br />Query: '.$sql;
			$this->error();
		else :
			$this->mySqliClose();
			return $this->result;
		endif;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Returns the results of the query as an object
	*
	* Example:
	*	$sql = "SELECT fieldA, fieldB FROM tableA";
	*	$sql = $db->query($sql);
	*
	*	while ($row = $db->fetch_object($sql) ) :
	*		echo $row->fieldA . ': ' . $row->fieldB;
	*	endwhile;
	*
	**************************************************************** */
	function fetch_object( $sql ) {
		if ( @$this->result ) :
			$uniqueIdentifier=rand();
			if ( $this->connect_type == 'mysql' ) :
				$$uniqueIdentifier=mysql_fetch_object( $sql );
			else :
				$$uniqueIdentifier=mysql_fetch_object( $sql );
			endif;
			return $$uniqueIdentifier;
			unset( $$uniqueIdentifier );
		endif;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Returns the results of the query as an array
	*
	* Example:
	*	$sql = "SELECT fieldA, fieldB FROM tableA";
	*	$sql = $db->query($sql);
	*
	*	while ($row = $db->fetch_object($sql) ) :
	*		echo $row['fieldA'] . ': ' . $row['fieldB'];
	*	endwhile;
	*
	**************************************************************** */
	function fetch_array( $sql ) {
		if ( @$this->result ) :
			$uniqueIdentifier=rand();
			$$uniqueIdentifier=mysql_fetch_array( $sql );
			return $$uniqueIdentifier;
			unset( $$uniqueIdentifier );
		endif;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Returns the number of rows returned in a query
	*
	**************************************************************** */
	function num_rows($result='') {
		if ( @$this->result ) :
			$uniqueIdentifier=rand();
			if (empty($result)) $result = $this->result;
			$$uniqueIdentifier=mysql_num_rows( $result );
			return $$uniqueIdentifier;
			unset( $$uniqueIdentifier );
		else :
			return 0;
		endif;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Returns the number of rows affected by a query
	*
	**************************************************************** */
	function rows_affected($result='') {
		if ( @$this->result ) :
			$uniqueIdentifier=rand();
			if (empty($result)) $result = $this->result;
			$$uniqueIdentifier = mysql_rows_affected( $result );
			return $$uniqueIdentifier;
			unset( $$uniqueIdentifier );
		else :
			return 0;
		endif;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Runs the mysql_result() function, but a little differently
	*
	* if $this->fetch_row(1), it will return the second field
	* of the first row
	*
	* if $this->fetch_row('field_name'), it will return the value
	* for 'field_name' in the first row
	*
	**************************************************************** */
	function fetch_row ( $fieldName ) {
		if (is_numeric( $fieldName )) {
			$fieldValue=mysql_result( $this->result, $fieldName );
		} else {
			$fieldValue=mysql_result( $this->result, 0, $fieldName );
		}
		return $fieldValue;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Returns the value of the specified field, in the specified
	* row.
	*
	* If no field or row is specified, it will default to first
	* row, first field
	*
	**************************************************************** */
	function fetch_value ( $sql='', $fieldName='', $row='' ) {
		$i=0;
		$fieldValue = false;

		if (empty($fieldName)) { $fieldName = 0; }
		if (empty($row)) { $row = 0; }
		$ret = array();
		$sql = $this->query($sql);
		if ($this->num_rows() > 0) {
			while ($rec = mysql_fetch_array( $sql )) {
				for ($a=0; $a < count($rec); $a++) {
					$ret[$i] = $rec;
				}
				$i++;
			}

			$fieldValue=$ret[$row][$fieldName];
		}

		return ($fieldValue);
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* Returns the results of the query as an array
	*
	* Example:
	*	$sql = "SELECT fieldA, fieldB FROM tableA"; // returns 4 rows
	*	$results = $db->to_array($sql);
	*
	*	$results[0]['fieldA'] = 'valueA 1';
	*	$results[0]['fieldB'] = 'valueB 1';
	*
	*	$results[1]['fieldA'] = 'valueA 2';
	*	$results[1]['fieldB'] = 'valueB 2';
	*
	*	$results[2]['fieldA'] = 'valueA 3';
	*	$results[2]['fieldB'] = 'valueB 3';
	*
	*	$results[3]['fieldA'] = 'valueA 4';
	*	$results[3]['fieldB'] = 'valueB 4';
	*
	* Example with foreach loop:
	*	foreach ($results as $key=>$result) :
	*		echo $result['fieldA'].'<br />'.$results['fieldB'];
	*	endforeach;
	*
	**************************************************************** */
	function to_array ( $sql='' ) {

		## keep the string value of the SQL statement in case of error
		$this->sql_txt = $sql;

		$i=0;
		$ret = array();
		$sql = $this->query($sql);
		if ( $this->connect_type == 'mysql' ) :
			if ( $sql ) :
				while ($row = mysql_fetch_assoc( $sql )) :
					for ($a=0; $a < count($row); $a++) :
						$ret[$i] = $row;
					endfor;
					$i++;
				endwhile;
			endif;
		else :
			if ( $sql ) :
				while ($row = mysqli_fetch_assoc( $sql )) :
					for ($a=0; $a < count($row); $a++) :
						$ret[$i] = $row;
					endfor;
					$i++;
				endwhile;
			endif;
		endif;
		return ($ret);
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

	/* ****************************************************************
	*
	* closes the database connection
	*
	* PHP nowadays does a really good job of trashing these connection
	* automatically. However, just to be safe, I typically call this
	* method in an include that is loaded after everything else
	*
	**************************************************************** */
	function close_db() {
		if ($this->db_link) :
			mysql_close($this->db_link);
		endif;
	}
	/* ****************************************************************
	* end :::
	**************************************************************** */

}
/* *********************************************************************************
* END :::
********************************************************************************* */
$db = new Framework_Database;
$db->connect();
?>