As shown in the E-R and database diagrams:
1) Each username shall have a single ToDo list instance made up of zero or more ToDoItem instances.
2) A ToDo list:
a) Is uniquly identified using an integer value automatically generated by the database.
b) Must have a username value. Each username value must be unique and must contain at least one upper or lower-case letter. Only upper and lower-case letters and the space character are allowed in a username.
3) A ToDoItem:
a) Is uniquely identified using the ToDo id value (a foreign key field) along with an integer value automatically generated by the database.
b) Must have a dateCreated. This value is created by the system instead of the user.
c) Must have a description. This value describes the to-do item and must contain at least one