How to validate presence of phone number or mobile phone

Rails Deployment
1

In my model of user.rb

there are phone number and mobile number.

i want to validate if phone number and mobile number are exist or
not(not neccessary to do both).

how to do that

2

Thriving K. wrote:

In my model of user.rb

there are phone number and mobile number.

i want to validate if phone number and mobile number are exist or
not(not neccessary to do both).

how to do that

Write following code in model.

validates_presences_of :field_name