1. Developing a FHIR Server
Using C# and MongoDb, Xml and Json
Ewout Kramer,
Furore

2. Architectural context
FHIR v3
HIS
LIMS
PACS v2
PHR
Comm.
Service
ETL
FHIR Msg
FHIR REST
FHIR
Use FHIR as the storage to your v2/v3 engine
Use FHIR as the exchange language for PHR data
Use FHIR as the common language for a Vendor Neutral Archive
CDR
VNA
Comm.
Service DB

3. Solution scenarios FHIR Resource JSON/XML POCO/POJO DBMS ORM
FHIR Parser
JSON/XML
POCO/POJO
NoSql (Xml/Json)
FHIR Parser
JSON/XML
NoSql (Json/Xml)
FHIR Validator
JSON/XML
XML
NoSql (Json)
FHIR Validator
FHIR REST
Processing
Configurability. Recompile versus configure.
Storage

4. Json and Xml Roundtrip? <XXX xmlns=“urn:foo”> <B a=“c” />
<C>One</C>
<C>Two</C>
<D>One</D>
<div>Not <b>so</b></div>
</XXX> {
“B”: { : “c” },
“C”: [ “One”, “Two” ],
“D” : “One”,
“div” :
{ “#text” : “Not ”,
“b” : “so” }

5. FHIR Xml and JSon guidelines
<Person xmlns=" <identifiers> <identifier> <type> <code>MR</code> <system>urn:hl7-org:sid/v2-0203</system> </type> <identifier> <system>oid: </system> <id>12345</id> </identifier> <assigner> <text>Acme Healthcare</text> </assigner> <period> <low> </low> </period> </identifier> </identifiers>
<text>
<status>generated</status> <xhtml xmlns=" <table> <tbody> <tr>
"Person" : {
"identifiers" :
[ { "identifier" :
{ "type" :
{ "code" : "MR",
"system" : "urn:hl7-org:sid/v2-0203“ } }
} ],
"text" : {
"status" : "generated",
"xhtml" : "<table><tbody><tr><td>Name</td>
<td>Peter James <b>Chalmers</b>
</table></tbody></table>"

6. Two ways of storing in MongoDb
var database = server.GetDatabase("test");
var collection = database.GetCollection<Entity>("entities");
var entity = new Entity { Name = "Tom" };
collection.Insert(entity);
var id = entity.Id;
BsonDocument nested = new BsonDocument {
{ "name", "John Doe" },
{ "address", new BsonDocument
{ "street", "123 Main St." },
{ "city", "Centerville" },
{ "zip", } } };
collection.Insert(nested);

7. Json -> XML -> Json -> Bson
What a detour….
Json -> XML -> Json -> Bson

9. Storing a resource as a record
ResourceRecord
RecordId, Version
State
CreationDate, Author
ResourceRecord
RecordId, Version
State
CreationDate, Author
ResourceRecord
RecordId, Version
State
CreationDate, Author
ResourceInstance
AsJson(), ToJson(), …
GetElement(), ReplaceElement()
ResourceId, Location, Type
FHIR Resource
Data (XML)

11. How do I do transactions/locking?
MongoDB does not use traditional locking or complex transactions with rollback, as it is designed to be lightweight and fast and predictable in its performance.  It can be thought of as analogous to the MySQL MyISAM autocommit model.  By keeping transaction support extremely simple, performance is enhanced, especially in a system that may run across many servers.

12. C A P Brewer’s CAP theorem Consistency, Availability and
Partition tolerance
Pick any two… A P

17. FIRST FHIR CONNECTATHON
26th Annual Plenary & Working Group Meeting
Sep 9, 2012 to Sep 14, 2012 - Baltimore, MD
(Dutchies take note: September 12th general elections!)
SATURDAY SEPTEMBER 8th
FIRST FHIR CONNECTATHON

18. db.things.find( { x : 3, y : "foo" } );
db.foo.find( { $and:
[ { a: { $lt: 10 } },
{ a: { $gt: 5 } }
] } )