Odoo 12 Development Cookbook - Third Edition

How it works...

In step 2, we declare an SQL SELECT query. This will return the average number of days a user holds a particular book. If you run this query in the PostgreSQL CLI, you will get a result based on your book data:

+---------------------------------------+-------+| name                                  | avg   ||---------------------------------------+-------|| Odoo 12 Development Cookbook          | 33    || PostgreSQL 10 Administration Cookbook | 81    |+---------------------------------------+-------+

Step 3 calls the execute() method on the database cursor stored in self.env.cr. This sends the query to PostgreSQL and executes it.

Step 5 uses the fetchall() method of the cursor to retrieve a list of rows selected by the query. This method returns a list of rows. In my case, ...