Odoo 12 Development Essentials - Fourth Edition

Setting values on to-many relation fields

For one-to-many and many-to-many fields, instead of a single ID, a list of related IDs is expected. Furthermore, several operations can be performed—we may want to replace the current list of related records with a new one, or append a few records to it, or even unlink some records.

To support write operations on to-many fields, we use a special syntax in the eval attribute. To write to a to-many field, we use a list of triples. Each triple is a write command that does different things according to the code used in the first element.

To overwrite the list of authors of a book, we would use the following code:

<field name="author_ids" 
       eval="[(6, 0,               [ref('res_partner_alexandre'),  ref('res_partner_holger')] ...