Adding a Flexible Query Mechanism to a Web Service

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Service-oriented Architecture (SOA), along with the growing use of discrete, self-contained business services has become widely recognized as the most relevant strategic direction for enterprise computing. One of the requirements for a well-designed SOA is that the services provide flexibility for use in future applications.

A flexible service for enterprise applications means implementing a query language in order to select and filter the large amount of information that may be accessible from the service. Structured Query Language (SQL) is a very powerful language that has been used for many years for accessing and processing data using the relational database management concepts.

DataDirect® OpenAccess™ can be used to add a SQL compliant query feature over the data being managed by the Web Service. For example, if you are exposing a service over a CRM type of an application, you can expose a query() method that can be called to return filtered data from the various object types accessible through that service. Say you want to get all accounts assigned to a sales person X:

select * from ACCOUNTS where MANAGER=’Joe  Smith’

OpenAccess was designed from ground up to allow the efficient processing of SQL queries over many types of data management mechanisms. The interface between the OpenAccess SQL engine and the customized code layer (what we call the Interface Provider, or IP) has been designed to allow efficient processing of SQL on top of legacy file structures, objects implemented in C++, .NET or Java, memory data stores, and many other data structures. This design allows the OpenAccess SQL engine to be embedded within a Web Service container to process the incoming query on the data managed by the application server.