<?php
/**
* Multi database connection class
*
*/
class DBConnection {
/**
* Current database type
*
* @var string
* @access private
*/
var $dbType = 'mysql';
/**
* Created connection handle
*
* @var resource
* @access private
*/
var $connectionID = null;
/**
* Handle of currenty processed recordset
*
* @var resource
* @access private
*/
var $queryID = null;
/**
* DB type specific function mappings
*
* @var Array
* @access private
*/
var $metaFunctions = Array();
/**
* Function to handle sql errors
*
* @var string
* @access private
*/
var $errorHandler = '';
/**
* Error code
*
* @var int
* @access private
*/
var $errorCode = 0;
/**
* Error message
*
* @var string
* @access private
*/
var $errorMessage = '';
/**
* Initializes connection class with
* db type to used in future
*
* @param string $dbType
* @return DBConnection
* @access public
*/
function DBConnection($dbType, $errorHandler = '')
{
$this->dbType = $dbType;
$this->initMetaFunctions();
if(!$errorHandler)
{
$this->errorHandler = Array(&$this,'handleError');
}
}
/**
* Set's custom error
*
* @param int $code
* @param string $msg
* @access public
*/
function setError($code,$msg)
{
$this->errorCode=$code;
$this->errorMessage=$msg;
}
/**
* Checks if previous query execution
* raised an error.
*
* @return bool
* @access public
*/
function hasError()
{
return !($this->errorCode == 0);
}
/**
* Caches function specific to requested
* db type
*
* @access private
*/
function initMetaFunctions()
{
$ret = Array();
switch($this->dbType)
{
case 'mysql':
$ret = Array(); // only define functions, that name differs from "dbType_<meta_name>"
break;
}
$this->metaFunctions = $ret;
}
/**
* Get's function for specific db type
* based on it's meta name
*
* @param string $name
* @return string
* @access private
*/
function getMetaFunction($name)
{
if( !isset($this->metaFunctions[$name]) )
{
if(function_exists($this->dbType.'_'.$name)) return $this->dbType.'_'.$name;
}
else
{
return $this->dbType.$name;
}
return false;
}
/**
* Try to connect to database server
* using specified parameters and set
* database to $db if connection made
*
* @param string $host
* @param string $user
* @param string $pass
* @param string $db
* @access public
*/
function Connect($host,$user,$pass,$db)
{
$func = $this->getMetaFunction('connect');
$this->connectionID = $func($host,$user,$pass) or trigger_error("Can't connect to db", E_USER_ERROR);
if($this->connectionID)
{
$this->setDB($db);
$this->showError();
}
}
/**
* Shows error message from previous operation
* if it failed
*
* @access private
*/
function showError($sql='')
{
$this->setError(0,''); // reset error
if($this->connectionID)
{
$func = $this->getMetaFunction('errno'); $this->errorCode = $func($this->connectionID);
if($this->hasError())
{
$func = $this->getMetaFunction('error'); $this->errorMessage = $func($this->connectionID);
if(is_array($this->errorHandler))
{
$func = $this->errorHandler[1];
$ret = $this->errorHandler[0]->$func($this->errorCode,$this->errorMessage,$sql);
}
else
{
$func = $this->errorHandler;
$ret = $func($this->errorCode,$this->errorMessage,$sql);
}
if(!$ret) exit;
}
}
}
/**
* Default error handler for sql errors
*
* @param int $code
* @param string $msg
* @param string $sql
* @return bool
* @access private
*/
function handleError($code,$msg,$sql)
{
echo '<b>Processing SQL</b>: '.$sql.'<br>';
echo '<b>Error ('.$code.'):</b> '.$msg.'<br>';
return false;
}
/**
* Set's database name for connection
* to $new_name
*
* @param string $new_name
* @return bool
* @access public
*/
function setDB($new_name)
{
if(!$this->connectionID) return false;
$func = $this->getMetaFunction('select_db');
return $func($new_name);
}
/**
* Returns first field of first line
* of recordset if query ok or false
* otherwise
*
* @param string $sql
* @return string
* @access public
*/
function GetOne($sql)
{
$row = $this->GetRow($sql);
if(!$row) return false;
return array_shift($row);
}
/**
* Returns first row of recordset
* if query ok, false otherwise
*
* @param stirng $sql
* @return Array
* @access public
*/
function GetRow($sql)
{
$sql .= ' '.$this->getLimitClause(0,1);
$ret = $this->Query($sql);
if(!$ret) return false;
return array_shift($ret);
}
/**
* Returns 1st column of recordset as
* one-dimensional array or false otherwise
* Optional parameter $key_field can be used
* to set field name to be used as resulting
* array key
*
* @param string $sql
* @param string $key_field
* @return Array
* @access public
*/
function GetCol($sql, $key_field = null)
{
$rows = $this->Query($sql);
if(!$rows) return $rows;
$i = 0; $row_count = count($rows);
$ret = Array();
if(isset($key_field))
{
while ($i < $row_count)
{
$ret[$rows[$i][$key_field]] = array_shift($rows[$i]);
$i++;
}
}
else
{
while ($i < $row_count)
{
$ret[] = array_shift($rows[$i]);
$i++;
}
}
return $ret;
}
/**
* Queries db with $sql query supplied
* and returns rows selected if any, false
* otherwise. Optional parameter $key_field
* allows to set one of the query fields
* value as key in string array.
*
* @param string $sql
* @param string $key_field
* @return Array
*/
function Query($sql, $key_field = null)
{
$query_func = $this->getMetaFunction('query');
$this->queryID = $query_func($sql,$this->connectionID);
if( is_resource($this->queryID) )
{
$ret = Array();
$fetch_func = $this->getMetaFunction('fetch_assoc');
if( isset($key_field) )
{
while( ($row = $fetch_func($this->queryID)) )
{
$ret[$row[$key_field]] = $row;
}
}
else
{
while( ($row = $fetch_func($this->queryID)) )
{
$ret[] = $row;
}
}
$this->Destroy();
return $ret;
}
$this->showError($sql);
return false;
}
/**
* Free memory used to hold recordset handle
*
* @access private
*/
function Destroy()
{
if($this->queryID)
{
$free_func = $this->getMetaFunction('free_result');
$free_func($this->queryID);
$this->queryID = null;
}
}
/**
* Returns auto increment field value from
* insert like operation if any, zero otherwise
*
* @return int
* @access public
*/
function getInsertID()
{
$func = $this->getMetaFunction('insert_id');
return $func($this->connectionID);
}
/**
* Returns row count affected by last query
*
* @return int
* @access public
*/
function getAffectedRows()
{
$func = $this->getMetaFunction('affected_rows');
return $func($this->connectionID);
}
/**
* Returns LIMIT sql clause part for specific db
*
* @param int $offset
* @param int $rows
* @return string
* @access private
*/
function getLimitClause($offset, $rows)
{
switch ($this->dbType) {
default:
return 'LIMIT '.$offset.','.$rows;
break;
}
}
/**
* Returns last error code occured
*
* @return int
*/
function getErrorCode()
{
return $this->errorCode;
}
/**
* Returns last error message
*
* @return string
* @access public
*/
function getErrorMsg()
{
return $this->errorMessage;
}
/**
* Correctly quotes a string so that all strings are escaped. We prefix and append
* to the string single-quotes.
* An example is $db->qstr("Don't bother",magic_quotes_runtime());
*
* @param s the string to quote
* @param [magic_quotes] if $s is GET/POST var, set to get_magic_quotes_gpc().
* This undoes the stupidity of magic quotes for GPC.
*
* @return quoted string to be sent back to database
*/
function qstr($s,$magic_quotes=false)
{
$replaceQuote = "\\'";
if (!$magic_quotes)
{
if ($replaceQuote[0] == '\\')
{
// only since php 4.0.5
$s = str_replace(array('\\',"\0"),array('\\\\',"\\\0"),$s);
//$s = str_replace("\0","\\\0", str_replace('\\','\\\\',$s));
}
return "'".str_replace("'",$replaceQuote,$s)."'";
}
// undo magic quotes for "
$s = str_replace('\\"','"',$s);
if($replaceQuote == "\\'") // ' already quoted, no need to change anything
{
return "'$s'";
}
else // change \' to '' for sybase/mssql
{
$s = str_replace('\\\\','\\',$s);
return "'".str_replace("\\'",$replaceQuote,$s)."'";
}
}
}
?>