[corona-dev] Corona's use of SDO and Data Mediator Services- how far?

["Everitt, Glenn" <Glenn.Everitt@xxxxxxxxxxxxx>]

Should Corona Collaboration framework standardize on SDO Data Graphs for objects in the Corona Client user interface and transferring of objects between tiers in the Corona Framework? 

 

Should Corona Collaboration Framework encapsulate data access to web services, jms, jdbc, xml using the Data Mediator Services returning SDO Data Graph Objects?

 

Should we also provide an option of returning repository objects as SDO Data Graphs?

 

 

Here is the basic idea of SDO and Data Mediator Service (DMS).  The Data Mediator talks with a Data Source creates an SDO Data Graph

and returns them to the client caller of the Data Mediator Service.   Diagram below is from this link: http://softwaresummit.com/2005/speakers/TostServiceDataObjects.pdf

 

 

 

The benefit of using Data Mediator Service and having all of the data returned as an SDO Data Graph is that your client can handle objects in a more consistent way.  The Data Graph interfaces are divided into 2 categories.  The first is a generic API where everything in the Data Graph is treated as a node.  The node has properties and a type.   The second is an object specific API with get/set method for managing all of the attributes of the object.  Some examples of data returned as Data Graphs from Data Mediator Services include:

 

-Web Service Call Results (Websphere supports this, Corona does this in a limited way today. I want to talk to Joel about expanding this capability.)

-JDBC Result Sets (Tuscany, Websphere support this)

-JMS Messages (I think Websphere ESB supports this) http://www-128.ibm.com/developerworks/websphere/techjournal/0604_tost/0604_tost.html

-EJB calls (WebSphere supports this)

-XML (Eclipse EMF project supports XML through its Data Mediator Service. )

 

We may want to use a Data Mediator Service to access information in our JCR repository.  The key point is the Data Mediator Service handles the connection details to the data source and provides a consistent API for the Client and a consistent Object Model for the client.  The Corona Client using the Data Mediator Services would include the ContextContainer and the Corona Client User Interface.

 

 

Discussion of using SDO and Data Mediator Service to produce SDO objects from a relational database. I think the relevant structures are Topology 4 on slide 17 and Topology 5 on slide 18  http://java.sys-con.com/read/46652.htm

 

WebSphere today supports DMS using EMF for

·    JDBC Data Mediator Service

·    EJB Data Mediator Service

The DMS provided by WebSphere are part of IBM’s commercial offering but shows what can be done with this approach.

 

This presentation shows the use of SDO in different architectural structures

http://softwaresummit.com/2005/speakers/TostServiceDataObjects.pdf

 

The Apache Tuscany Project ( the SCA implementation project ) provides utilizes SDO objects  http://incubator.apache.org/tuscany/sdo_index.html

Tuscany also has created a Data Access Service (or Data Mediator Service) to relational data see this link: http://incubator.apache.org/tuscany/RDB_DAS_white_paper_v-0.2.pdf

 

We could possibly use the Tuscany Data Access Service to Relational Databases some issues are resolved:

-          release date of Tuscany

-          incompatibility between Eclipse SDO and Tuscany SDO.

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