Using the Adapter With Relational Databases

The adapter can process SQL statements embedded in XML documents and forward them to an RDBMS (or server component) as a request. The RDBMS returns the data to the adapter, which returns the data to the client.

The adapter supports the capture of events from applications that write to a database. It captures the data and performs operations based on the content of table rows. The adapter reads one or more rows from the table and creates an XML document representing the column data in each row.

Additional business logic facilities can be applied to the constructed XML document, including transformation, validation, security management, and application processing. Transformations by business logic can include deleting rows or altering column values. The resulting XML is formatted and sent to the adapter for further processing.

The listener can:

• Monitor data changes by repeatedly performing an SQL query.

  The SQL listener also supports customized user exits with Java™ classes to define custom operations on the row sets.

• Be configured to operate one row at a time or to operate on sets of data.

  You can configure the listener to send events only to a business process workflow when a specified minimum number of rows become available in the source RDBMS.

• Allow the configuration of an optional SQL post-query statement.

  The statement performs specific RDBMS operations after the adapter sends the row set (formatted as XML) to a business process workflow.

  The default operation is to delete the rows that were transferred to the workflow.

  Other options can include moving the rows to an archive table or marking the rows with an SQL UPDATE.

• Support complex configurations.

  For example, you may want to extract information periodically from a base table and incorporate reference data from an additional table. Records cannot be deleted from the base table and reference table.

  In this case, the adapter uses a temporary table to maintain the sequenced rows in the base table. The temporary table contains a starting value for the sequence. It holds the last value of the sequence field processed by the RDBMS listener, enabling multiple event operations to collect updates while avoiding sending duplicates to a business process workflow.

• Support user-defined exits.

  User-defined exits can be implemented to enable more complex programming or external database operations.

  For example, an operating system program can be executed to facilitate an import or export process within a custom application.