OpenERP/Odoo model relationship XML syntax

Question

I'm working with OpenERP 7.0. The code below is from the file addons/project/security/project_security.xml

Please explain me where the number 4, 6 and 0 are from? Which place in the document I can consult about this?

<record id="group_project_user" model="res.groups">
    <field name="name">User</field>
    <field name="category_id" ref="base.module_category_project_management"/>
</record>

<record id="group_project_manager" model="res.groups">
    <field name="name">Manager</field>
    <field name="category_id" ref="base.module_category_project_management"/>
    <field name="implied_ids" eval="[(4, ref('group_project_user'))]"/>
    <field name="users" eval="[(4, ref('base.user_root'))]"/>
</record>

<record model="ir.ui.menu" id="base.menu_definitions">
    <field name="groups_id" eval="[(6,0,[ref('group_project_manager')])]"/>
</record>

Answer 1

For a many2many field, a list of tuples is expected. Here is the list of tuple that are accepted, with the corresponding semantics:

(0, 0,  { values })    link to a new record that needs to be created with the given values dictionary
(1, ID, { values })    update the linked record with id = ID (write *values* on it)
(2, ID)                remove and delete the linked record with id = ID (calls unlink on ID, that will delete the object completely, and the link to it as well)
(3, ID)                cut the link to the linked record with id = ID (delete the relationship between the two objects but does not delete the target object itself)
(4, ID)                link to existing record with id = ID (adds a relationship)
(5)                    unlink all (like using (3,ID) for all linked records)
(6, 0, [IDs])          replace the list of linked IDs (like using (5) then (4,ID) for each ID in the list of IDs)

Example:
[(6, 0, [8, 5, 6, 4])] sets the many2many to ids [8, 5, 6, 4]

For a one2many field, a list of tuples is expected. Here is the list of tuple that are accepted, with the corresponding semantics:

(0, 0,  { values })    link to a new record that needs to be created with the given values dictionary
(1, ID, { values })    update the linked record with id = ID (write *values* on it)
(2, ID)                remove and delete the linked record with id = ID (calls unlink on ID, that will delete the object completely, and the link to it as well)

Example:
[(0, 0, {'field_name':field_value_record1, ...}), (0, 0, {'field_name':field_value_record2, ...})]

I hope this clears your doubts

Thanks And Regards