review articles

Doi: 10.1145/2184319.2184340

Exploring the technology trends in basic,
integrated, and cloud data services.

By MiChAeL J. CARey, niCoLA onose,
AnD MiChALis Pe TRoPouLos
Data
services

today’s BUsIness praCtICes require access to enterprise data by both external as well as internal applications. Suppliers expose part of their inventory to retailers, and health providers allow patients to view their health records. but how do enterprise data owners ensure access to their data is appropriately restricted and has predictable impact on their infrastructure? In turn, application developers sitting on the “wrong side” of the Web from their data need a mechanism to find out which data they can access, what their semantics are, and how they can integrate data from multiple enterprises. Data services are software components that address these issues by providing rich metadata, expressive languages, and APIs for service consumers to use to send queries and receive data from service providers.

Data services are a specialization of Web services that can be deployed on top of data stores, other services, and/or applications to encapsulate a wide

range of data-centric operations. In contrast to traditional Web services, services that provide access to data need to be model-driven, offering a semantically richer view of their underlying data and enabling advanced querying functionality. Data service consumers need access to enhanced metadata, which is both machine-readable and human-readable, such as schema information. This metadata is needed to use or integrate entities returned by different data services. For example, a getCustomers data service might retrieve customer entities, while getOrdersByCID retrieves orders given a customer id. In the absence of any schema information, the consumer is not sure if he or she can compose these two services to retrieve the orders of customers. Moreover, consumers of data services can utilize a query language and pass a query expression as a parameter to a data service; they can use metadata-guided knowledge of data services and their relationships to formulate queries and navigate between sets of entities.

Modern data services are descendants of the stored procedure facilities provided by relational database systems, which allow a set of SQL statements and control logic to be parameterized, named, access-controlled, and then called from applications that

 

key insights

Data services differ from traditional Web services in that they serve as “fronts” for data and are based on a richer model of that data.

The growing importance of data
services in the movement toward
a hosted-services world is evidenced
by the number of contexts within
which they have been utilized in recent
years: data publishing, data exchange
and integration, service-oriented
architectures (soA), data as a service
(Daas), and most recently, cloud
computing.
While data services were initially
conceived to solve problems in the
enterprise world, the cloud is now making
data services accessible to a much
broader range of consumers.