Features of the Database as a Web Service Consumer

Using the database as a Web Service consumer offers the following features:

• Consuming Web Services form Java-in-the-database - Provides an easy-to-use interface for calling-out web services, thereby insulating developers from low-level SOAP programming. Java classes running in the database can simply and directly invoke external web services by using the previously loaded Java proxy or dynamic invocation.
• Consuming Web Services from SQL and PL/SQL - Allows any SQL-enabled tool or application to transparently and easily consume dynamic data from external web services. After Exposing Web Services methods as Java Stored PRocedures, A PL/SQL wrapper on top of a Java stored procedures hides all Java and SOAP programming details from the SQL client.
• Web Services Data Source - Enables Application and Data integration by turning external web service into an SQL data source, making external Web services appear as regular SQL tables. This table function represents the output of calling external web services and can be used in an SQL query.

Web Service Data Sources (Virtual Table Support)

To access data (returned from single or multiple Web service invocations) through a database table, create a virtual table through a Web service data source. This table function allows you to query a set of returned rows as though it were a table.

The client invokes a Web service and the results are stored in a virtual table in the database. You can pass result sets from function to function, allowing you to set up a sequence of transformation without a table holding intermediate results. To reduce memory usage, you can return the result set rows a few at a time within a function.

By using Web services with the table function, you can manipulate a range of input values (from single or multiple Web services) as a real table. In the following example, the inner SELECT creates rows whose columns are used as arguments for invoking the CALL_WS Web service call-out. The table expression could be used in other SQL queries, for constructing views, and so on.

SELECT <some-columns> 
FROM
  TABLE(WS_TABFUN(CURSOR(SELECT s FROM <some_table>))),
WHERE...