Relational Database Handler

In order to provide support for a Sensor Observation Service (SOS) implementation Hyrax will need a handler that allows it to access data in a Relational Database Management System (RDBMS). (This requirement stems from the observation that many of our stake holders store their in situ measurement data in RDBMSs)

It is anticipated RDBMS handler will have a much broader application than just SOS related data sets.

Use Cases

1. Adding the RDH to the BES
2. RDH handles bes:showCatalog request
3. RDH handles a DDX request
4. RDH handles a DDS request
5. RDH handles a DAS request
6. RDH handles a DAP2 data request

Definitions

row set

A row set is an object which encapsulates a set of rows. Database tables are row sets. A database view is a row set. SQL queries return row sets. SQL JOIN operations take row sets as input and produce row sets.

Background

In the past a Java servlet called the DODS Relational Database Server (DRDS) was used to provide DAP access to RDBMS holdings. However this older implementation has a number of shortcomings that preclude it's direct use in our current server architecture:

• No longer supported.
• Uses the Java DAP implementation
• Not a BES module
• Significant memory limitations
• Difficult to configure/localize

Although there has been continuing interest in a DRDS replacement within the OPeNDAP community, bo funding has been available to develop a soution until recent;y. The IOOS project has a need to provide a Sensor Observation Service (SOS) interface for Hyrax. Since much of the sensor data is already held in RDBMS system it is a natural and necessary time to develop a DRDS replacement.