Why is the database name required?
Alongside the address, an Odoo connection asks for a database name, and this field cannot be left empty. The reason is Odoo's architecture: a single Odoo server can host several databases, each belonging to a different company. The address says which server to reach; the database name says which company on that server to connect to. On Odoo Online the database name is usually the same as your subdomain.
An API key is used instead of a password. You generate it under user preferences → account security and never enter the account's normal password — which is also what lets the connection work on accounts with two-factor authentication enabled.
