How do you make a backwards R?

E-R Diagram - patient database and link analysis.. HOW TO MAKE??? please help!!?

• 1. E-R design - patient database *Consider a hospital, w/c keeps track of doctors, patients, and their medical history 1. for both patients and doctors, we record their unique SSN, and their name and address 2. for doctors only, we also record their specialty ('surgeon', 'opthalmologist' etc). it is possible that a doctor come to our hospital as a patient 3. patients come visits, for w/c we record the date, the diagnosing doctor and the diagnosis (ex, "flu", "laryngitis", etc) - for every visit, there is only one diagnosing doctor (not necessarily the same every time) - no patient makes two visits in the same day - there may be more that one diagnoses for a single visit (ex "borken leg and " broken arm" 4. in a visit, a doctor may prescribe zero or more drugs; for each prescription, we want to record the drug name and the dosage ( a string, eg., "1 pill evry 6 hours") 2. E-R design - link analysis consider a law enforcement agency, w/c keep tracks of suspected people (convicted criminals or not), and their contacts, specifically - for every person, we want to record a unique 'suspect-id', his/her name and address - for convicted criminals, we record a list of their past crimes, each described as a string (ex 'bank robbery', 'assault', 'obstruction of justice') - for non-convicted people, we record their current employer - for each financial exchange (loan, payment, etc) b/n two people, we record the date, time and amount - for each communication b/n two people, we record the date, time and type ('phone', 'email') - for each suspicious appearance of a person, we record the date, time and the address, along with the other people that happened to be in the same place and at the same time. - assume that times are recorded at the minute level, so it is impossible to have a person do two communication/appearances/financial-exch… simultaneously. TO DO: 1. create the E-R diagram 2. indicate the primary keys, candidate keys, weak entities, discriminators, multivated attributes, derived attributes, and cardinalities of relationship 3. turn the E-R diagram into tables (underline the primary keys, and list any additional candidate keys) *the typical use of such database is 'link analysis': law enforcement wants to find out who has too many connections w/ other suspects, and thus try to discover money-laundering rings and other indirect connections between criminals. thus, typical queries in such database would be 'find all suspects that met more than 3 time in the month before the bank robbery'.

• Answer:

  I can make this ERD..but there are some confusions for me in it.. In E-R design - link analysis what is meant by Communication between two people ? and what is meant by financial exchange between two people? is that the payment of patient to hospital at each visit? and please also clear the last two points of E-R design - link analysis..