Web Services uses industry-standard mechanisms to provide easy access to remote content and applications, regardless of the provider’s platform, location, implementation, or data format. Client applications can query and retrieve data from Oracle databases and invoke stored procedures using standard web service protocols. There is no dependency on Oracle-specific database connectivity protocols. This approach is highly beneficial in heterogeneous, distributed, and non-connected environments.
You can call into the database from a Web Service, using the database as a service provider. This allows you to leverage existing or new SQL, PL/SQL, Java stored procedures, or Java classes within an Oracle database. You can access and manipulate database tables from a Web service client.
Use JPublisher to generate Java wrappers that correspond to database operations, then deploy the wrappers as Web services in Oracle AS. Figure demonstrates how you use JPublisher to publish PL/SQL packages, SQL objects, collections, and packages as Java classes. Once published, these objects can be accessed by any Web service through an OC4J Web services servlet.
Web Services Calling In to the Database
Features of the Database as a Web Service Provider
Using the database as a Web Service provider offers the following features:
- Enhanced PL/SQL Web Services – Improves PL/SQL Web Services by extending Web Services support for additional PL/SQL types including CLOB, BLOB, XMLType, REfCursor, PL/SQL records and tables. This enables you to use most of your existing PL/SQL packages as Web Services.
- Java-in-the-database Web Services – Exposes existing Java classes deployed in the database as Web Services. Java classes implementing data-related services can be migrated between the middle tier and the database. Java portability results in database independence.
- SQL Query Web Services – Leverages warehousing or business intelligence queries, data monitoring queries, and any predefined SQL statements as web services.
- DML Web Services – Offers secure, persistent, transactional and scalable logging, auditing and tracking operations implemented via SQL DML, as web services. DML web services are implemented as atomic or group/batch insert, update, and delete operations.