I noticed there are 2 kinds of constraints on Odoo ERP. But I want to know what is the difference between _sql_constraints vs _constraints?
_sql_constraints = {
('email_uniq', 'unique(email)', ' Please enter Unique Email id.')
}
_constraints=[
(_check_qty_and_unitprice, u'Qty must be more than 0',['product_qty', 'cost_unit']),
]
_sql_constraints means it will set constraint on postgresql database side.
_sql_constraints = [
('email_uniq', 'unique(email)', ' Please enter Unique Email id.'),
]
Where:
email_uniq means constraint name,
unique(email) means unique is name of constraint. email is a field name which constraint will apply on that field.
'Please enter Unique Email id.' is a message and it will display on pop-up window when constraint would be violated.
_constraints is python constraint. We can give our logic to set constraints. For example:
_constraints = [
(_check_qty_and_unitprice, u'Qty must be more than 0', ['product_qty', 'cost_unit']),
]
Where :
_check_qty_and_unitprice is a function name where we need to apply our logic.
'Qty must be more than 0' is a message and it will display on pop-up window when constraint would be violated (the python function returns False).
['product_qty', 'cost_unit'] is a list of field name which means constraint will fire for these two fields.
As of the new Odoo API python constraint have a new and simpler decorator. The below example can be written like this:
from openerp.exceptions import ValidationError
@api.constraints('product_qty', 'cost_unit')
def _check_something(self):
for record in self:
if record.product_qty < 1:
raise ValidationError("Qty must be more than 0")
