Draw the ER diagram.
Phone call logs: Ginormous State University (GSU) maintains an office phone network. This question describes the database needed to keep track of individual phones. The university also keeps a record of utilization of the network for internal calls. An internal call is one placed from one GSU office phone to another GSU office phone. Each phone is identified by a unique phone number and is designated as either a personal phone or a common?area phone (the database should remember which). For each phone, the system should also store the date of installation and the employee “responsible” for the phone. For personal phones, the person responsible is typically the person in whose office the phone is located. Some employees may be responsible for more than one phone – for example, because the person has more than one office, each with its own phone, or because one person may be deemed responsible for more than one common?area phone. Employees are identified by a unique university ID number. This database should store each employee’s first name, middle name/initial, last name, and primary e?mail address. The database should also remember in which room each phone is installed. Each building in the university has a unique building number, a building name (such as “McPherson Hall”), and a street address. All buildings in the university are located in the same city, state, and zip code, so the database need only store the street address. Each room has a number which is unique within its building (that is, there is only one “130 McPherson Hall,” but there may be a room numbered “130” in a different building. The university physical plant department is able to supply a database containing all the valid room number/building combinations, along with the square footage and type (office, classroom, waiting area, etc.) for each room. Finally, the database should keep a record of all internal calls, including from which phone the call was placed, to which phone it was placed, whether the call was answered (a yes/no field), the date and time the call started, and the date and time it ended. You may assume that only one call at a time can be placed from any given phone. Design a database to store this information. Draw an ER diagram, and write a database design outline. You may add “ID” fields where necessary.