There are a lot of manuals. I am trying to create an database to hold information of these documents. But, there is a small problem. How can I give meaningful id to the manuals? Are there any standard or logic behind the giving meaningful id to the documents? If there is no standard, can you tell me how I should do that?

example:

 table :

         manual id | manual name

EDIT:

Not Meaningful ID 

     1        or  M1        or   foo
     2            C2             bar
     3            P123           name
    ...           ...            ...
     (i)          (ii)            (iii)

(i) Not meaningful for me because if some item deleted, there can be gap. ex 1 33 100.

(ii) random character can be confusing when one try to give a name to new manual

(iii) Why giving name is not preferred is because finding a name to the manual as ID is hard after 500 manuals.

Meaningful :

New ID

* Can be easily produced even if after 1000 manuals
* Should not be so complicated