Virtual Campus (VC) is a social media firm that specializes in creating virtual meeting places for students, faculty, staff, and others associated with different college campuses. VC was started as a student project in a database class at Cyber University, an online polytechnic college, with headquarters in a research park in San Diego, California. The following parts of this exercise relate to different phases in the development of the database VC now provides to client institutions to support a threaded discussion application. Your assignment is to draw an ERD to represent each phase of the development of the VC database and to answer questions that clients raised about the capabilities (business rules) of the database in each phase. The description of each phase will state specific requirements as seen by clients, but other requirements may be implied or possibly should be implemented in the design slightly differently than the clients might see them, so be careful to not limit yourself to only the specifics provided. (20 pts) The first phase was fairly simplistic. A client may maintain several social media sites (e.g., for intercollegiate sports, academics, local food and beverage outlets, or a specific student organization). Each site has attributes of Site Identifier, Site Name, Site Purpose, Site Administrator, and Site Creation Date. Any person may become a participant in any public site. Persons need to register with the client's social media presence to participate in any site, and when they do the person is assigned a Person Identifier; the person provides IUs or her Nickname and Status (e.g., student, faculty, staff, or friend, or possibly several such values); the Date Joined the site is automatically generated. A person may also include other information, which is available to other persons on the site; this information includes Name, Twitter Handle, Facebook Page link, and SMS Contact Number. Anyone may register (no official association with the client is necessary). An account is created each time a person registers to use a particular site. An account is described by an Account ID, User Name, Password, Date Created, Date Terminated, and Date/Tune the person most recently used that account. Using an account, a person creates a posting, or message, for others to read. A posting has a Posting Date/ Time and Content. The person posting tile message may also add a Date when tile posting should be made invisible to other users. A person is permitted to have multiple accounts, each of which is for only one site. A person, over time, may create multiple postings from an account. The ERD to represent this initial phase is shown below: Phase I:

Please modify this ERD based on the next rules: Phase II (15 pts): (THIS IS THE QUESTION THAT NEEDS TO BE ANSWERED, MODIFY THE ERD ABOVE BASED ON THE NEXT RULES) The database for the first phase certainly provided only the basics. VC quickly determined that two additional features needed to be added to the database design, as follows (draw a revised ERD to represent the expanded second phase database): From their accounts, persons might respond to postings with an additional posting. Thus, postings may form threads, or networks of response postings, which then may have other response postings and so forth. It also became important to track not only postings but also when persons from their accounts read a posting. This requirement is needed to produce site usage reports concerning when postings are made, when they are read and by whom, frequency of reading, etc.