First, HL7 is an organization. It defines a number of different standards (v2, v3, CDA, FHIR and others). So when talking about using HL7 to share data, it’s best to be specific.
In terms of whether you should use a specific HL7 standard to interact with other systems, it depends on what standards those other systems support. In general, communication between systems within a single hospital are primarily done using HL7 v2. Communication across organizations varies - sometimes v2, sometimes CDA and an increasing amount is FHIR. Communication between mobile applications and any other systems are almost entirely FHIR.
thanks lloyd for your response.
so As per your response its clear for me that i have to used FHIR standard because i am developing web and mobile application.
and i am little bit confused about database schema because i am following mdds database dictionary to build a server (beck end) database but while i am implementing FHIR HL7 standard JSON web services for communicating with client side web and mobile application than in webserivces there are another classes and metadata so i am not able to manage it. please give me suggestion about it.
It’s quite common for database structures to be completely different from the FHIR interface you share data with. You’ll need write code to map between the two.