PHP - Using $this When Not In Object Context

Hello.
I am now dumbfounded (once again).
I am using $this inside a class.
I honestly have no idea what is going on. If anyone could give me a pointer that would be brilliant.
Code: [Select]
/*
  * List of functions in this class in order (construct and destruct are the only functions not in alphabetical order)
  * Construct
* BooleanValue
* BuildColumns
* Connect
* Clean
* Delete
* Disconnect
* EndTransaction
* Error
* Insert
* IsConnected
* Kill
* LastInsertID
* Log
* Query
* RollbackTransaction
* RowCount
* Select
* StartTransaction
* Update
* Where
* Destruct
*/

class MySQL extends MySQLi {
private $host = HOST;
private $user = USER;
private $pass = PASS;
private $data = DATA;
private $port = PORT;
private $charset = CHARSET;

const quote = "'"; // what quote to use

/* Internal vars */
private $lastID = "";
private $lastResult = "";
private $queries = "";
private $link = 0;
private $timeStart = 0;
private $timeEnd = 0;
private $timeTotal = 0;
private $errorString = "";
private $errorNo = 0;
private $in_transaction = false;
private $queryQueue = "";


/*
* Construct
* Starts the connection unless autoconnect = false
*/
public function __construct($autoconnect = true) {
$autoconnect === true ? $this->Connect() : false;
}
/*
* End construct
***************************************************************************************************/

/*
* BooleanValue
* Determins whether the input is a boolean value, or can be converted into a boolean value
*/
static function BooleanValue($value) {
$value = self::Clean($value);
if(gettype($value) == "boolean") {
if($value == true) {
return true;
} else {
return false;
}
} elseif(is_numeric($value)) {
if($value > 0) {
return true;
} else {
return false;
}
} else {
$str = strtoupper(mysqli_real_escape_string($this->link, trim($value)));
if($str == "ON" || $str == "SELECTED" || $str == "CHECKED" || $str == "YES" || $str == "Y" || $str == "TRUE" || $str == "T") {
return true;
} else {
return false;
}
}
}
/*
* End BooleanValue
***************************************************************************************************/

/*
* BuildColumns
* Builds columns for use with SQL statements
*/
static function BuildColumns($columns, $addQuotes = true, $showAlias = true) {
if($addQuotes) {
$quote = self::quote;
} else {
$quote = "";
}
switch(gettype($columns)) {
case "array":
$sql = "";
$i = 0;
foreach($columns as $key => $value) {
$key = self::Clean($key);
$value = self::Clean($value);
if($i == 0) {
$sql = $quote.$value.$quote;
$i = 1;
} else {
$sql .= ", ".$quote.$value.$quote;
}
if($showAlias && is_string($key) && (!empty($key))) {
$sql .= " AS ".$quote.$key.$quote."'";
}
}
break;
case "string":
$columns = self::Clean($columns);
return $quote.$columns.$string;
break;
default;
return false;
break;
}

return $sql;

}
/*
* End BuildColumns
***************************************************************************************************/

/*
* Connect
* Connects to the database
*/
public function Connect() {
$this->link = @mysqli_connect($this->host, $this->user, $this->pass, $this->data, $this->port);
$this->IsConnected();
}
/*
* End Connect
***************************************************************************************************/

/*
* Clean
* Cleans input
*/
static function Clean($value) {
$this->IsConnected();
$value = ltrim($value);       
  $value = rtrim($value);
  $value = mysqli_real_escape_string($this->link, $value);
  return $value;
}
/*
* End Clean
***************************************************************************************************/

/*
* Delete
* Deletes a record from the database
*/
public function Delete($table, $whereArray) {
$sql = "DELETE FROM ".$table;
$sql .= self::Where($whereArray);
}
/*
* End Delete
***************************************************************************************************/

/*
* Disconnect
* Disconnects from the database
*/
public function Disconnect() {
if($this->IsConnected()) {
mysqli_close($this->link);
}
}
/*
* End disconnect
***************************************************************************************************/

/*
* EndTransaction
* Ends the transaction, saving all data to the database
*/
public function EndTransaction() {
$this->IsConnected();
if($this->in_transaction) {
if(!mysqli_query($this->link, "COMMIT")) {
$this->RollbackTransaction();
} else {
$this->in_transaction = false;
return true;
}
} else {
$this->Error("Not in a transaction", -1);
return false;
}
}
/*
* End EndTransaction
***************************************************************************************************/

/*
* Error
* Handles Errors
*/
public function Error($errstr = "", $errno = 0) {
try {
if(strlen($errstr) > 0) {
$this->errorString = $errstr;
} else {
$this->errorString = @mysqli_error($this->link);
if(!strlen($this->errorString) > 0) {
$this->errorString = "Unknown error";
}
}
if($errno <> 0) {
$this->errorNo = $errno;
} else {
$this->errorNo = @mysqli_errno($this->link);
}
} catch(Exception $e) {
$this->errorString = $e->getMessage();
$this->errorNo = -999;
}
$this->Kill();
}
/*
* End Error
***************************************************************************************************/

/*
* Insert
* Inserts a record into the database
*/
public function Insert($table, $valuesArray) {
$columns = self::BuildColumns(array_keys($valuesArray), false);
$values  = self::BuildColumns($valuesArray, true, false);
$sql = "INSERT INTO ".$table." (".$columns.") VALUES (".$values.")";
$this->queryQueue .= $sql;
}
/*
* End Insert
***************************************************************************************************/

/*
* IsConnected
* Checks if there is a connection
*/
public function IsConnected() {
if(@mysqli_ping($this->link)) {
return true;
} else {
$this->Error();
return false;
$this->RollbackTransaction();
$this->Kill("No connection present");
}
}
/*
* End IsConnected
***************************************************************************************************/

/*
* Kill
* Rollsback anychanges and kills the script
*/
public function Kill() {
$this->RollbackTransaction();
if(!$this->errorString) {
$this->errorString = "Unknown";
}
if(!$this->errorNo) {
$this->errorNo = -999;
}
die("<br /><br /><strong>An error has occured.<br />".$this->errorString."<br />".$this->errorNo);
}
/*
* End Kill
***************************************************************************************************/

/*
* LastInsertID
* Returns the last inserted ID
*/
public function LastInsertID() {
return $this->lastID;
}
/*
* End LastInsertID
***************************************************************************************************/

/*
* Log
* Logs all MySQL queries
*/
static function Log($page, $utime, $wtime, $mysql_time, $sphinx_time, $mysql_count_queries, $mysql_queries) {
/*$table = "mysql-".date("Ymd");
$sql = "INSERT DELAYED INTO ".$table." (ip, page, utime, wtime, mysql_time, sphinx_time, mysql_count_queries, mysql_queries, user_agent) VALUES ("self::quote.$_SERVER['REMOTE_ADDR'].self::quote.", ".self::quote.$page.self::quote.", */
}
/*
* End Log
***************************************************************************************************/

/*
* Query
* Exectues all queries
*/
public function Query($sql) {
$this->IsConnected();

$this->timeStart = microtime(true);

$this->queries = $sql;
$this->StartTransaction();
$this->lastResult = @mysqli_query($this->link, $sql);
if(!$this->lastResult) {
$this->RollbackTransaction();
$this->Error();
}
$this->EndTransaction();
if(strpos(strtolower($sql), "insert") === 0) {
$this->lastID = mysqli_insert_id($this->link);
if($this->lastID === false) {
$this->Error();
} else {
return $this->lastResult;
//$this->queryQueue = "";
}
} elseif(strpos(strtolower($sql), "select") === 0) {
$this->LastID = 0;
}

$this->timeEnd = microtime(true);
$this->timeTotal = ($this->timeEnd - $this->timeStart);
$removeE = explode('E', $this->timeTotal);
$this->timeTotal = $removeE[0];
echo $this->queryQueue;
}
/*
* End Query
***************************************************************************************************/

/*
* RollbackTransaction
* Un-does the changes made
*/
private function RollbackTransaction() {
$this->IsConnected();
if(!mysqli_query($this->link, "ROLLBACK")) {
$this->Error("Rollback failed. Manual cleanup required");
return false;
} else {
$this->in_transaction = false;
return true;
}
}
/*
* End RollbackTransaction
***************************************************************************************************/

/*
* RowCount
* Returns the amount of rows effected from the last query
*/
public function RowCount() {
return mysqli_num_rows($this->lastResult);
}
/*
* End RowCount
***************************************************************************************************/

/*
* Select
* Selects rows
* USAGE:
* $result = $sql->Select("users", array("username" => "james"));
* while($row = mysqli_fetch_array($result)) {
* echo $row['password'];
* }
*/
public function Select($table, $whereArray = null, $columns = null, $sortColumns = null, $sortAscending = true, $limit = null) {
if(!is_null($columns)) {
$sql = self::BuildColumns($columns);
} else {
$sql = "*";
}
$sql = "SELECT ".$sql." FROM ".$table;
if(is_array($whereArray)) {
$sql .= self::Where($whereArray);
}
if(!is_null($sortColumns)) {
$sql .= " ORDER BY ".self::BuildColumns($sortColumns, true, false). " ".($sortAscending ? "ASC" : "DESC");
}
if(!is_null($limit)) {
$sql .= " LIMIT ".$limit;
}
self::Query($sql);
$return = "";
return $this->lastResult;
}
/*
* End Select
***************************************************************************************************/

/*
* StartTransaction
* Starts the transaction
*/
private function StartTransaction() {
if(!$this->IsConnected()) {
die();
}
if(!$this->in_transaction) {
if(!mysqli_query($this->link, "START TRANSACTION")) {
$this->Error();
return false;
} else {
$this->in_transaction = true;
return true;
}
} else {
$this->Error("Already in a transaction");
}
}
/*
* End StartTransaction
***************************************************************************************************/

/*
* Update
* Updates the rows
*/
public function Update($table, $valuesArray, $whereArray = null) {
$sql = "";
$i = 0;
foreach($valuesArray as $key => $value) {
$key = self::Clean($key);
$value = self::Clean($value);
if($i == 0) {
$sql = $key." = ".self::quote.$value.self::quote;
$i = 1;
} else {
$sql .= ", ".$key." = ".self::quote.$value.self::quote;
}
}
$sql = "UPDATE ".$table." SET ".$sql;
if(is_array($whereArray)) {
$sql .= self::Where($whereArray);
}
self::Query($sql);
return $this->lastResult;
}
/*
* End Update
***************************************************************************************************/

/*
* Where
* Select rows where X
*/
public function Where($whereArray) {
$where = "";
foreach($whereArray as $key => $value) {
$key = self::Clean($key);
$value = self::Clean($value);
if(strlen($where == 0)) {
if(is_string($key)) {
$where = " WHERE ".$key." = ".self::quote.$value.self::quote;
} else {
$where = " WHERE ".self::quote.$value.self::quote;
}
} else {
if(is_string($key)) {
$where .= " AND ".$key." = ".self::quote.$value.self::quote;
} else {
$where .= " AND ".self::quote.$value.self::quote;
}
}
}
return $where;
}
/*
* End where
***************************************************************************************************/

/*
* Destruct
* Closes the connection and cleans up
*/
public function __destruct() {
if($this->queryQueue) {
$this->Query($this->queryQueue);
}
$this->Disconnect();
}
/*
* End destruct
***************************************************************************************************/
}
The code I am using to get the error is this:
Code: [Select]
$sql = new Mysql;
$sql->Insert("users", array("username" => "James"));
$sql->Insert("users", array("username" => "fds"));
$sql->Insert("users", array("username" => "le"));

Thanks.
EDIT: Added code to call the error.