Odoo follows a multi-tier architecture, and we can identify three main tiers: Data, Logic, and Presentation:
The Data tier is the lowest-level layer, and is responsible for data storage and persistence. Odoo relies on a PostgreSQL server for this. PostgreSQL is the only supported RDBMS, and this is a design choice. So, other databases such as MySQL are not supported. Binary files, such as attachments of documents or images, are usually stored in a filesystem.
The Logic tier is responsible for all the interactions with the data layer, and is handled by the Odoo server. As a general rule, the low-level database should only ...