Understanding external identifiers
An external identifier, also called XML ID, is a human-readable string identifier that uniquely identifies a particular record in Odoo. They are important when loading data into Odoo.
The actual database identifier for a record is an automatically assigned sequential number, and there is no way to know ahead of time what ID will be assigned for each record, during module installation. The external identifiers provide a way to reference a related record without the need to know the actual database ID assigned to it. The XML ID provides a convenient alias for the database ID so that we can use it whenever we need to reference a particular record.
Records defined in Odoo module data files use XML IDs. One reason for this is to avoid creating duplicate records when upgrading a module. The module upgrade will load the data files into the database again. We want it to detect the already existing records in order for them to be updated, instead of creating duplicate...
