12) [MANDATORY] An offer is a record in which an administrator advertises something. The system must store the following data about them: an instantiation moment (in the past), a heading (not blank, shorter than 76 characters), a summary (not blank, shorter than 101 characters), an availability period (at least one day after the offer is instantiated and must last for at least one week), a price (positive, possibly nought), and an optional link with further information.
12) [MANDATORY] An offer is a record in which an administrator advertises something. The system must store the following data about them: an instantiation moment (in the past), a heading (not blank, shorter than 76 characters), a summary (not blank, shorter than 101 characters), an availability period (at least one day after the offer is instantiated and must last for at least one week), a price (positive, possibly nought), and an optional link with further information.