Of treatment per week for each patient (though it is currently unclear to what use this information will be put).ġ. Required for which patients and when and it should be capable of calculating the cost The system will also need to track what treatments are Some staff are paid part time and doctorsĪnd care assistants work varying amounts of overtime at varying rates (subject to grade). The system must record details concerning patient treatmentĪnd staff payment. Each patient is requiredĪ certain number of times per day and for varying lengths of time.
Initially the system will be concerned solely with drug treatment. To the patients, a number of these are associated with each ward. Usually each patient will be assigned a single doctor, Before discussing the procedure, let's look atĪssigned to them. Relationships provide the structure needed to draw information from multiple entities.ĭeveloping an ERD requires an understanding of the system and its components. There are three basic elements in ER models:Įntities are the "things" about which we seek information.Īttributes are the data we collect about the entities. They also set the stageįor the design of databases later on in the SDLC. Entity Relationship Diagrams Information Systemsĭata models are tools used in analysis to describe the data requirements and assumptions in the system from a top-down perspective.