Basically i have two database tables

Patient
Patient Number | Patient Last Name | Patient First Name | Patient Address


Patient Charges
Item Description | Item Code | Patient Number | Amount

How do I make a diagram showing the relationship between the entities Patient and Patient Charges?

You will need to look closely at patient and patient charges tables to determine the type of relationship. Can a patient have a charge without being in the patient table? Should a patient have a single charge or can the patient have multiple charges? This will help you in determining the relationship between the tables. When you are talking about a diagram are you talking about UML?

You ideally should have three tables

patients
number, lastname, firstname, address

items
itemcode, description

patient_items
patientnumber, itemcode, amount (is this amount of item i.e. three pills or price?)

a new row in the third table for each item a patient gets.

Thanks allot!