What is the difference between these facebook access tokens? -

I am developing an FB application which can manage pages but I need to make it clear:

What

$ page_info = $ facebook-> The difference between the API ("/ $ page_id? Fields = access_token");

and

$ aToken = $ facebook-> GetAccessToken ();

I think they generate different tokens, but I am unsure about how I should store the database for offline posting, and what each does?

Thank you ..

retrieves a page access token:

• You use it to work on behalf of the page

  Other (by default in PHP SDK):

  < Li> The user used to perform actions on behalf of the user retrieves access tokens. The main difference here is that in order to obtain a token using a page, you must request permission from the user to manage_pages .