Identification Numbers (IDs)
What is an ID?
An ID is a unique identifier for an item. It is used to identify the item in the database and is usually used as a primary key in the database.
Types of IDs
Runnings IDs
Running IDs or running numbers are the most basic type of IDs. They are created by the system from either a starting number or the last number in the database and incremented by 1 for each new item.
This type of IDs can be incremented based on month or year (optionally) and is useful for items that needs to be printed on paper, such as invoices, receipts, ARCs.
Unique IDs
Unique IDs, sometimes called UUID or GUID, are unique identifiers that are generated by the system. They are 128-bit numbers that are guaranteed to be unique across space and time or practical purposes.
INFO
As per Wikipedia, the number of UUIDs generated to have at least 1 collision is 2.71 quintillion. That is 1 billion UUIDs per second for 85 years.
This type of IDs particularly useful for items that are stored across multiple databases, so that each database does not need to keep track of the IDs of the items in the other databases.
Example of unique id (UUID): e1c01874-e88b-43cd-b2a5-12bf8eb238a4