<?php
// +-------------------------------------------------------------------------+
// | Generic MySQL database access management class. This can be used for |
// | implementing database access in other classes requiring it. Features |
// | include: |
// | - suppressing of error messages and error management |
// | - methods to control showing of error messages |
// | - methods to perform and manage database connections and queries |
// | - [methods to navigate through the database resuklts and queries] |
// | - Begin, Commit, and Rollback database Transactions if supported |
// | |
// | The goal behind this class was to have an easy to extend MySQL |
// | management |
// | class. Hopefully, others will find it useful. |
// | |
// | Note: Although not tested on systems running PHP3, it should be |
// | compatible. If you run into any trouble, e-mail me with exact |
// | details of the problem. This 'class' is being provided as is |
// | without any written warranties whatsoever. |
// +-------------------------------------------------------------------------+
// | Author: Amir Khawaja |
// | E-mail: amir@gorebels.net |
// | Date Created: May 15, 2001 |
// | Last Modified: $Date: 2002/06/28 20:54:12 $ |
// | Version: 1.3.1 |
// | License: GPL |
// +-------------------------------------------------------------------------+
class DB
{
/**
* global variables
*/
var $dbhost = 'localhost'; // default database host
var $dblogin; // database login name
var $dbpass; // database login password
var $dbname; // database name
var $dblink; // database link identifier
var $queryid; // database query identifier
var $error = array(); // storage for error messages
var $record = array(); // database query record identifier
var $totalrecords; // the total number of records received from a select statement
var $last_insert_id; // last incremented value of the primary key
var $previd = 0; // previus record id. [for navigating through the db]
var $transactions_capable = false; // does the server support transactions?
var $begin_work = false; // sentinel to keep track of active transactions
/**
* get and set type methods for retrieving properties.
*/
function get_dbhost()
{
return $this->dbhost;
} // end function
function get_dblogin()
{
return $this->dblogin;
} // end function
function get_dbpass()
{
return $this->dbpass;
} // end function
function get_dbname()
{
return $this->dbname;
} // end function
function set_dbhost($value)
{
return $this->dbhost = $value;
} // end function
function set_dblogin($value)
{
return $this->dblogin = $value;
} // end function
function set_dbpass($value)
{
return $this->dbpass = $value;
} // end function
function set_dbname($value)
{
return $this->dbname = $value;
} // end function
function get_errors()
{
return $this->error;
} // end function
/**
* End of the Get and Set methods
*/
/**
* Constructor
*
* @param String $dblogin, String $dbpass, String $dbname
* @return void
* @access public
*/
function DB($dblogin, $dbpass, $dbname, $dbhost = null)
{
$this->set_dblogin($dblogin);
$this->set_dbpass($dbpass);
$this->set_dbname($dbname);
if ($dbhost != null) {
$this->set_dbhost($dbhost);
}
} // end function
/**
* Connect to the database and change to the appropriate database.
*
* @param none
* @return database link identifier
* @access public
* @scope public
*/
function connect()
{
$this->dblink = @mysql_pconnect($this->dbhost, $this->dblogin, $this->dbpass);
if (!$this->dblink) {
$this->return_error('Unable to connect to the database.');
}
$t = @mysql_select_db($this->dbname, $this->dblink);
if (!$t) {
$this->return_error('Unable to change databases.');
}
if ($this->serverHasTransaction()) {
$this->transactions_capable = true;
}
return $this->dblink;
} // end function
/**
* Disconnect from the mySQL database.
*
* @param none
* @return void
* @access public
* @scope public
*/
function disconnect()
{
$test = @mysql_close($this->dblink);
if (!$test) {
$this->return_error('Unable to close the connection.');
}
unset($this->dblink);
} // end function
/**
* Stores error messages
*
* @param String $message
* @return String
* @access private
* @scope public
*/
function return_error($message)
{
return $this->error[] = $message.' '.mysql_error().'.';
} // end function
/**
* Show any errors that occurred.
*
* @param none
* @return void
* @access public
* @scope public
*/
function showErrors()
{
if ($this->hasErrors()) {
reset($this->error);
$errcount = count($this->error); //count the number of error messages
echo "<p>Error(s) found: <b>'$errcount'</b></p>\n";
// print all the error messages.
while (list($key, $val) = each($this->error)) {
echo "+ $val<br>\n";
}
$this->resetErrors();
}
} // end function
/**
* Checks to see if there are any error messages that have been reported.
*
* @param none
* @return boolean
* @access private
*/
function hasErrors()
{
if (count($this->error) > 0) {
return true;
} else {
return false;
}
} // end function
/**
* Clears all the error messages.
*
* @param none
* @return void
* @access public
*/
function resetErrors()
{
if ($this->hasErrors()) {
unset($this->error);
$this->error = array();
}
} // end function
/**
* Performs an SQL query.
*
* @param String $sql
* @return int query identifier
* @access public
* @scope public
*/
function query($sql)
{
if (empty($this->dblink)) {
// check to see if there is an open connection. If not, create one.
$this->connect();
}
$this->queryid = @mysql_query($sql, $this->dblink);
if (!$this->queryid) {
if ($this->begin_work) {
$this->rollbackTransaction();
}
$this->return_error('Unable to perform the query <b>' . $sql . '</b>.');
}
$this->previd = 0;
return $this->queryid;
} // end function
/**
* Grabs the records as a array.
* [edited by MoMad to support movePrev()]
*
* @param none
* @return array of db records
* @access public
*/
function fetchRow()
{
if (isset($this->queryid)) {
$this->previd++;
return $this->record = @mysql_fetch_array($this->queryid);
} else {
$this->return_error('No query specified.');
}
} // end function
/**
* Moves the record pointer to the first record
* Contributed by MoMad
*
* @param none
* @return array of db records
* @access public
*/
function moveFirst()
{
if (isset($this->queryid)) {
$t = @mysql_data_seek($this->queryid, 0);
if ($t) {
$this->previd = 0;
return $this->fetchRow();
} else {
$this->return_error('Cant move to the first record.');
}
} else {
$this->return_error('No query specified.');
}
} // end function
/**
* Moves the record pointer to the last record
* Contributed by MoMad
*
* @param none
* @return array of db records
* @access public
*/
function moveLast()
{
if (isset($this->queryid)) {
$this->previd = $this->resultCount()-1;
$t = @mysql_data_seek($this->queryid, $this->previd);
if ($t) {
return $this->fetchRow();
} else {
$this->return_error('Cant move to the last record.');
}
} else {
$this->return_error('No query specified.');
}
} // end function
/**
* Moves to the next record (internally, it just calls fetchRow() function)
* Contributed by MoMad
*
* @param none
* @return array of db records
* @access public
*/
function moveNext()
{
return $this->fetchRow();
} // end function
/**
* Moves to the previous record
* Contributed by MoMad
*
* @param none
* @return array of db records
* @access public
*/
function movePrev()
{
if (isset($this->queryid)) {
if ($this->previd > 1) {
$this->previd--;
$t = @mysql_data_seek($this->queryid, --$this->previd);
if ($t) {
return $this->fetchRow();
} else {
$this->return_error('Cant move to the previous record.');
}
} else {
$this->return_error('BOF: First record has been reached.');
}
} else {
$this->return_error('No query specified.');
}
} // end function
/**
* If the last query performed was an 'INSERT' statement, this method will
* return the last inserted primary key number. This is specific to the
* MySQL database server.
*
* @param none
* @return int
* @access public
* @scope public
* @since version 1.0.1
*/
function fetchLastInsertId()
{
$this->last_insert_id = @mysql_insert_id($this->dblink);
if (!$this->last_insert_id) {
$this->return_error('Unable to get the last inserted id from MySQL.');
}
return $this->last_insert_id;
} // end function
/**
* Counts the number of rows returned from a SELECT statement.
*
* @param none
* @return Int
* @access public
*/
function resultCount()
{
$this->totalrecords = @mysql_num_rows($this->queryid);
if (!$this->totalrecords) {
$this->return_error('Unable to count the number of rows returned');
}
return $this->totalrecords;
} // end function
/**
* Checks to see if there are any records that were returned from a
* SELECT statement. If so, returns true, otherwise false.
*
* @param none
* @return boolean
* @access public
*/
function resultExist()
{
if (isset($this->queryid) && ($this->resultCount() > 0)) {
return true;
}
return false;
} // end function
/**
* Clears any records in memory associated with a result set.
*
* @param Int $result
* @return void
* @access public
*/
function clear($result = 0)
{
if ($result != 0) {
$t = @mysql_free_result($result);
if (!$t) {
$this->return_error('Unable to free the results from memory');
}
} else {
if (isset($this->queryid)) {
$t = @mysql_free_result($this->queryid);
if (!$t) {
$this->return_error('Unable to free the results from memory (internal).');
}
} else {
$this->return_error('No SELECT query performed, so nothing to clear.');
}
}
} // end function
/**
* Checks to see whether or not the MySQL server supports transactions.
*
* @param none
* @return bool
* @access public
*/
function serverHasTransaction()
{
$this->query('SHOW VARIABLES');
if ($this->resultExist()) {
while ($this->fetchRow()) {
if ($this->record['Variable_name'] == 'have_bdb' && $this->record['Value'] == 'YES') {
$this->transactions_capable = true;
return true;
}
if ($this->record['Variable_name'] == 'have_gemini' && $this->record['Value'] == 'YES') {
$this->transactions_capable = true;
return true;
}
if ($this->record['Variable_name'] == 'have_innodb' && $this->record['Value'] == 'YES') {
$this->transactions_capable = true;
return true;
}
}
}
return false;
} // end function
/**
* Start a transaction.
*
* @param none
* @return void
* @access public
*/
function beginTransaction()
{
if ($this->transactions_capable) {
$this->query('BEGIN');
$this->begin_work = true;
}
} // end function
/**
* Perform a commit to record the changes.
*
* @param none
* @return void
* @access public
*/
function commitTransaction()
{
if ($this->transactions_capable) {
if ($this->begin_work) {
$this->query('COMMIT');
$this->begin_work = false;
}
}
}
/**
* Perform a rollback if the query fails.
*
* @param none
* @return void
* @access public
*/
function rollbackTransaction()
{
if ($this->transactions_capable) {
if ($this->begin_work) {
$this->query('ROLLBACK');
$this->begin_work = false;
}
}
} // end function
} // end class
?>
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