| That's the database id. Well-designed databases usually include an integer that counts up starting from one for all of your records. This number is known as the primary key and it's automatically programmed to increment. You happened to be given the number 4 when you were added to the database and that number uniquely identifies you.
Take note that I have not defined a primary key above; I have given an example of a primary key. A primary key is a key which is unique for each user and is the primary identifier for a given row.
Hope that helps. |