^{3.5: A dentist's office needs to keep information about patients, the number of visits they make to the office, work that must be performed, procedures performed during visits, charges and payments for only one dentist so there is no need to store information about the dentist in the database. There are several hundred patients. Patients make many visits, and the database should store information about the services performed during each visit and the changes for each of the services. There is a standard list of charges, kept outside of the database. The office uses three dental laboratories that provide supplies and services, such as fabricating dentures. Draw a complete ER diagram for this example.}

^{3.11 Develop an EE- Diagram for the dental group described above. Expand it by assuming that there are multiple dentists with some of the dentists being surgeons, who can perform oral surgery. Also assume some of the professionals are dental hygienists, who can perform routine work such as cleaning and taking x-rays A patient typically begins an ordinary visit by starting with a dental hygienist who performs routine work, and then a dentist who does a checkup during the same initial visit. The work needed is usually determined at this visit. If follow-up visits are required, each of the next visits will be with one dentist. If a patient requires oral surgery, at least one of his or her visits must be with one of the surgeons even though the rest of the work needed might be performed by his or her regular dentist. When surgery is performed, there must be a qualified assistant present. Only some of the hygienists are qualified to assist in surgeries. Assume this database does not keep track of appointments, only of actual visits, work, billing and payments.}