Java DataBase Connectivity Mediator Service

The Java Database Connectivity (JDBC) Data Mediator Service (DMS) is the Service Data Objects (SDO) component that connects to any database that supports JDBC connectivity. It provides the mechanism to move data between a DataGraph and a database.

A regular JDBC call returns a result set in a tabular format. This format does not directly correspond to the object-oriented data model of Java, and can complicate navigation and update operations. When a client sends a query for data through the JDBC DMS, the JDBC result set of tabular data is transformed into a DataGraph composed of related DataObjects. This enables clients to navigate through a graph to locate relevant data rather than iterating through rows of a JDBC result set. After altering the DataGraph, all of the changes can be committed together and propagated back to the database by the JDBC DMS. Between the processes of being populated and being committed, the DataGraph is disconnected from the database, and there are no locks held on the data accessed. Being disconnected allows multiple changes to be made to the graph without making additional round trips to the database, improving performance.

The JDBC DMS is created with backend-specific metadata. The metadata defines the structure of the DataGraph that is produced by the DMS, as well as the query to be used against the back end.

 

See also

Metadata for the Data Mediator Service
SDO data object types
JDBC mediator supplied query
JDBC mediator generated query
JDBC mediator transactions
JDBC mediator integration with presentation layer
JDBC mediator paging
JDBC mediator serialization

 

Related Tasks

Using the Java Database Connectivity data mediator service for data access

 

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