Getting Integrity Error while create new record

http://52.74.26.127:8069/ ERP: admin/password DB:- openerp Sales -> Sales Order -> Create a new Sales Order -> Save we get error while create any record such as sale order, purchase order Integrity Error:

duplicate key value violates unique constraint “sale_order_pkey” DETAIL: Key (id)=(31) already exists.

This post duplicates another one, that I moved to the Bahmni category: Getting "Integrity Error" while create new record