An Internet store sends emails to customers and would like to use a database to keep track of
which messages are sent to which customers. A message has a message id (mId), a subject
(subject), and a body (body). A customer is identified by the email address (email), and
customer’s data includes the attributes name, sex, householdSize, and address. When an
email is sent, the date (sendDate) is recorded. You can assume any reasonable domains for
these attributes