mysql全部換成mysqli 應該怎么寫代碼?

<?php?
/**
?*?連接數據庫
?*?@return?resource
?*/
function?connect(){
	$link=mysql_connect(DB_HOST,DB_USER,DB_PWD)?or?die("數據庫連接失敗Error:".mysql_errno().":".mysql_error());
	mysql_set_charset(DB_CHARSET);
	mysql_select_db(DB_DBNAME)?or?die("指定數據庫打開失敗");
	return?$link;
}

/**
?*?完成記錄插入的操作
?*?@param?string?$table
?*?@param?array?$array
?*?@return?number
?*/
function?insert($table,$array){
	$keys=join(",",array_keys($array));
	$vals="'".join("','",array_values($array))."'";
	$sql="insert?{$table}($keys)?values({$vals})";
	mysql_query($sql);
	return?mysql_insert_id();
}
//update?imooc_admin?set?username='king'?where?id=1
/**
?*?記錄的更新操作
?*?@param?string?$table
?*?@param?array?$array
?*?@param?string?$where
?*?@return?number
?*/
function?update($table,$array,$where=null){
	foreach($array?as?$key=>$val){
		if($str==null){
			$sep="";
		}else{
			$sep=",";
		}
		$str.=$sep.$key."='".$val."'";
	}
		$sql="update?{$table}?set?{$str}?".($where==null?null:"?where?".$where);
		$result=mysql_query($sql);
		//var_dump($result);
		//var_dump(mysql_affected_rows());exit;
		if($result){
			return?mysql_affected_rows();
		}else{
			return?false;
		}
}

/**
?*	刪除記錄
?*?@param?string?$table
?*?@param?string?$where
?*?@return?number
?*/
function?delete($table,$where=null){
	$where=$where==null?null:"?where?".$where;
	$sql="delete?from?{$table}?{$where}";
	mysql_query($sql);
	return?mysql_affected_rows();
}

/**
?*得到指定一條記錄
?*?@param?string?$sql
?*?@param?string?$result_type
?*?@return?multitype:
?*/
function?fetchOne($sql,$result_type=MYSQL_ASSOC){
	$result=mysql_query($sql);
	$row=mysql_fetch_array($result,$result_type);
	return?$row;
}


/**
?*?得到結果集中所有記錄?...
?*?@param?string?$sql
?*?@param?string?$result_type
?*?@return?multitype:
?*/
function?fetchAll($sql,$result_type=MYSQL_ASSOC){
	$result=mysql_query($sql);
	while(@$row=mysql_fetch_array($result,$result_type)){
		$rows[]=$row;
	}
	return?$rows;
}

/**
?*?得到結果集中的記錄條數
?*?@param?unknown_type?$sql
?*?@return?number
?*/
function?getResultNum($sql){
	$result=mysql_query($sql);
	return?mysql_num_rows($result);
}

/**
?*?得到上一步插入記錄的ID號
?*?@return?number
?*/
function?getInsertId(){
	return?mysql_insert_id();
}