We are interested in storing basic information about hospitals, doctors, patients and their illness. Each hospital houses several patients. Patients may be registered with multiple hospitals (possibly for different illnesses). Each doctor is employed by a hospital, and may attend to multiple patients in the hospital. We want to store some basic information about each of the entities involved. For instance, a hospital may be characterized by an id, name, and location, a patient may have an id, date of birth, information about illnesses, hospitals attending, with joining dates, etc. 

(a) Write a simple DTD for this application. 

(b) Create a sample XML document respecting your DTD, and containing information about a few hospitals, patients, and doctors. 

Write a XML Schema document that marks up the given schema letter (contact, salutation, paragraph, closing, signature) contact (name, address1, address2, city, state, zip, phone) Contact contains a type attribute. Paragraph element contains the message content of the letter. Closing element contains text like “Yours truly”, “Sincerely”, etc., By default each element occur only once unless otherwise as stated in the following. Include the facets for the following: a) type can contain either value sender or receiver. b) contact element appears exactly two times. c) paragraph element can appear between 1 to infinite times. d) phone number contains 12 digits in the pattern (+91 98203 38722).