The recent development wave in the Enterprise Application Integration (EAI) domain promotes Service- Oriented Architecture (SOA) and one of its implementation technologies that is Web Services (WSs). Recently, Data Services (DSs) have risen as a new form of services that are specifically optimized for real-time data integration demands. Despite the role that WSs and DSs could both play in addressing enterprise application issues, there is still a lack of architectures and approaches to methodologically design solutions to these issues. In this paper we propose an architecture along with an approach that both make WSs and DSs work hand-in-hand during the exercise of integrating enterprise applications, whereby WSs and DSs are supported by reusable software components, which we refer to as Business Objects (BOs). In this architecture, BOs abstract the complexity and disparity of data resources and thus,constitute their unique access points; WSs interface changes in BOs; and DSs interface only retrieval of the status of BOs. WSs/DSs-BOs combination is looked atfrom four interfaced levels, namely: (L1) enterprise application, (L2) service (specialized into Web service and Data service), (L3) business object, and (L4) data sources. The four levels are connected as follows: (I1:L1/L2) composition, (I2: L2/L3) matching, and (I3: L3/L4) access.