ok in simplest terms im having a problem developing a relationship between 4 entities. they are as follows:
physician: PH_ID,PH_Name
patient: P_ID,MRN,P_Name
Order:O_ID,O_Date,O_Time
Treatment:T_Code,T_Name

now my problem is that it states that a physican MAY order AND perform any number of services/treatments for a patient or not perform any treatment. after this i assume that order is a associative entity between patient and physician since it really seems to have no distinguishing features besides its ID.it also goes on saying that a treatment or service may be performed on any number of patients, and a patient may have any number of treatments performed or ordered by any number of physicians. for all treatment and services rendered, the hospital wants to record the physician ordering the treatment, treatement date and time, and the results. i say it could possibly be a tenary but im not quite sure how to do it. any additional information needed can be asked for. please i am in desperae need of help.

what im looking for is how to relate them to draw an entity relationship diagram