Relational Fields and Widgets In Odoo

A many2one field is used to link the current object to another object which acts as a parent for this object. In simple terms, when we can show the records of another model and link it with the current child model using a many2one relation.

Syntax for writing a Many2one Field:

field_name = fields.Many2one(comodel name=’model.model (parent model) ’, string=’Field Name’)

Here, as we can see we write the parent model and the name/string which is the name of the field to be displayed.

For example, here we have a custom model, we’’ll try to link with the ‘res.partner’ model as a parent model. So, we can link the parent model with our custom model.

Now as we can see, we can create/edit and delete records of the parent model from here. We can restrict this option on the field.

In the xml file, we can write like this :

          <field name="many2onefield" options="{'no_create': True, 'no_create_edit':True}" />

This will restrict the access for the user to create or edit records of the parent model through Many2one field here.

We can also filter the records shown here in the Many2one field. We can use the domain parameter to filter records based on conditions in the Many2one field.

It is a type of relational field and it provides the option to create relation between the child model & multiple rows of the parent model. This type of field can be used in cases where the user wants to store multiple records of the parent model and create a connection between those records and the current record through an inverse Many2one Field.

Syntax for writing an One2many field:

field_name = fields.One2many(comodel name=’model.model (parent model) ’, inverse_name=’name_of_the_inverse_field’, string=’Field Name’)

Here, comodel name (name of the parent model) and the inverse field name are mandatory parameters for creating an One2many relation.

The inverse field name is a Many2one field which should be present in the parent model. The comodel for this Many2one field is the current model. This inverse Many2one field is the key to linking the relationship between the records.

For example, in the custom model, we can create an One2many field like this

This type of field is used to create bidirectional multiple relationships between two different models.

This field can be used to create a table between two models. Any record on one side of the table can access any number of records on the other side of the table.

Syntax for writing Many2many field:

field_name = fields.Many2many(comodel name=’model.model’ ,  'relation between objects', ‘column1’, ‘column2’, string=’Field Name’)

The comodel name is the mandatory parameter here.

For example, we can create a Many2many field like this: