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Use the Enterprise JavaBeans data mediator service for data access

 

The following steps use code samples to describe a simple instance of how to create the Enterprise JavaBeans data mediator service (DMS) metadata.

 

Procedure

  1. A mediator instance is created using one of the create methods on the mediator factory (com.ibm.websphere.sdo.mediator.ejb.MediatorFactory) as in the following example

    import com.ibm.websphere.sdo.mediator.ejb.Mediator; import com.ibm.websphere.sdo.mediator.ejb.MediatorFactory; import com.ibm.webpshere.ejbquery.QueryException; import commonj.sdo.DataObject;
     try{
     String[] query =  { "select d.deptno,d.name from DeptBean as d" }; 
     Mediator m = MediatorFactory.getInstance().createMediator( query, null);
     DataObject root = m.getGraph();
    } catch (QueryException e) { ... } 
    

  2. There are 3 different forms of the createMediator method. The arguments are explained below.

    createMediator( query, parms)  createMediator( query, parms, schema ) createMediator( query, parms, schema,  typeMap,  pattern)
    

    The arguments to the createMediator method are:

    String query array of EJB query statements
    Object parms values for input parameters of the query statements
    Eclass* schema the EClass of the root DataObject
    Map* typeMap a java.util.Map that maps EJB Abstract Schema Names from the query statement into Eclass names
    int* pattern the pattern used for containment
     
    * used only when using caller provided schema



Enterprise JavaBeans Data Mediator Service

 

Related Reference


DataGraph schema
Example: Using query arguments with EJB mediator