title: Database schema design strategy for pharmacy and drug prescriptions
body: <p>I am in the process of designing a small database application for a health center in my local community. The health center can receive both In &amp; Out-Patients.</p>
  
  <p>The one area i am not sure of how best it should be implemented is how to bill the patient automatically from the drugs/medication they have be given. I don't want the user to type in the name and price of the drugs given to the patient. I want to automate it with a list of all available drugs and their <strong>CURRENT</strong> prices in a table so that the user just selects a drug from a list &amp; i the software should be able to determine the total. </p>
  
  <p>I also want to maintain the history of drugs over time. Some thing like drug <strong>XXX</strong> was selling at $1234 in January, $4567 in September, $12 in 2008. So if i am to print a receipt for a patient who visited in 2008, the patient should be billed at the rates of 2008 not the drug current rate.</p>
  
  <p>I am just asking for some general guidance and suggestions on the best database schema of a scenario related to my problem description above.</p>
  
  <p>Thanks a lot.</p>