Question

I’m confused about simple problem:

• What is the difference between the active record and the native query?

• If I have a trouble when coding CI, what should i do? are there trouble shoot? what fiter should i use?

• What is the difference between CI session and PHP session

Thanks for your answer

Here’s what I found about the difference, but still does not make me statisfied:

The Session class permits you maintain a user’s “state” and track their activity while they browse your site. The Session class stores session information for each user as serialized (and optionally encrypted) data in a cookie. It can also store the session data in a database table for added security, as this permits the session ID in the user’s cookie to be matched against the stored session ID. By default only the cookie is saved. If you choose to use the database option you’ll need to create the session table as indicated below.

Answer 1

CodeIgniter’s "Active Record" isn’t what the real active record is all about. An active record is like your database in PHP form. you interface with it using PHP than using sql queries. it’s like having that feeling that the database data is in PHP rather than in the database.

In CI, their active record is just a plain old "query builder" which build your SQL query in a clean, OOP-looking way and returns a cleanly formatted result thanks to several methods that format it to your liking (like result_array() for an array-formatted result, or result() for an object-formatted result).

Active record is an approach to accessing data in a database. A database table or view is wrapped into a class. Thus, an object instance is tied to a single row in the table. After creation of an object, a new row is added to the table upon save. Any object loaded gets its information from the database. When an object is updated the corresponding row in the table is also updated. The wrapper class implements accessor methods or properties for each column in the table or view.

The framework CodeIgniter has a query builder it calls "ActiveRecord", but which doesn’t implement the ActiveRecord pattern. Instead it implements what the user guide refers to as a modified version of the pattern. The ActiveRecord functionality in CodeIgniter can be achieved by using either CodeIgniter DataMapper library or CodeIgniter Gas ORM library. (Wikipedia)

CI also uses sessions, much like PHP sessions the difference is where it’s stored.

When a page is loaded, the session class will check to see if valid session data exists in the user’s session cookie. If sessions data does not exist (or if it has expired) a new session will be created and saved in the cookie. If a session does exist, its information will be updated and the cookie will be updated. With each update, the session_id will be regenerated. (http://codeigniter.com/user_guide/libraries/sessions.html)

unlike PHP where session data remains in the server and identified with the cookie sent or a passed session id, CI encodes it’s session data into the cookie itself. that’s also why you need a session "key" prior to using sessions to encrypt your session data because storing sessions in cookies is unsafe. why they do this, i don’t know, maybe to optimize the server and avoid storing data to it, sacrificing load speeds