Database

The Database refers to a collection of information that could be used by any person, written and compiled by Shaun Hastings and Clay Kaczmarek, who were members of the Assassin Order, for use within the Animus virtual machine.

Information
The database held records detailing assassination targets, allies, contacts, monuments, buildings, cities, documents, Glyphs, Rifts, Assassin's Tombs, Romulus Lairs and other people, places, and events that the Assassins Ezio Auditore and Connor Kenway came across during their lifetime, as viewed by their descendant Desmond Miles.

Pre-coma
Before Desmond Miles was put into a comatose state, the database was maintained by Shaun Hastings, and whenever Ezio saw something of interest, he could flag the database entry into Desmond's view, for the purpose of gaining greater knowledge about the entry's subject.

With the database being maintained from the outside of the Animus, Shaun or Rebecca could add comments or details of their own, including mentions of Glyphs and other important items of interest in the database.

It could also help Desmond reach tombs, Glyphs and other specific places whenever he needed to.

Coma
During the time when Desmond fell into a coma, due to the events that happened in the Colosseum, he was sent into the Black Room to recover. Because of this, Shaun could no longer monitor his activities when reliving Ezio's life, with the virtual construct of Clay Kaczmarek (also known as Subject 16), taking on his role and writing database entries for Desmond to read.

Clay also added in some comments to help Desmond within the Animus, but unlike Shaun and Rebecca, he wrote it within the database entry itself.

Trivia

 * The database commonly has false information on birth years. For example, Francesco de' Pazzi and Vieri de' Pazzi, who are father and son, are stated to have an age difference of 10.
 * Some of the characters present in Assassin's Creed II do not appear in the database.
 * Most of the files appear to have been obtained from Abstergo with multiple references pointing out to this.