20) data re A. Time-sensitive B. Time-variant er time and for which one must keep a history of the C. Historical D. Change-based 2. (10 pts) Define the two "integrity rules", 3. (10pts) List five advantages of DBMS. 4. (20pts) This problem is concerned with modeling of a database that contains information on researchers, academic institutions, and collaborations among researchers. A researcher can either be employed as a professor or a lab assistant. There are three kinds of professors: assistant, associate, and full professors. The following should be stored: - For each researcher, his/her name, year of birth, and current position (if any). - For each institution, its name, country, and inauguration year. - For each institution, the names of its schools (e.g. School of Law, School of Business, School of Engineering...). A school belongs to exactly one institution. - An employment history, including information on all employments (start and end date, position, and what school). - Information about co-authorships, i.e., which researchers have co-authored a research paper. The titles of common research papers should also be stored. - For each researcher, information on his/her highest degree (BSc, MSc or PhD), including who was the main supervisor, and at what school. - For each professor, information on what research projects (title, start date, and end date) he/she is involved in, and the total amount of grant money for which he/she was the main applicant. Question: Using the Crow's Foot Notation, create an ERD for the data set described above. Make sure to indicate all cardinality constraints specified above. The E/R diagram should not contain redundant entity sets, relationships, or attributes. Also, use relationships whenever appropriate. If you need to make any assumptions, include them in your