Although many scientific applications rely on data stored in databases, most workflow management systems are not capable of establishing database connections during workflow execution. For this reason, e-Scientists have to use different tools before workflow submission to access their datasets and gather the required data on which they want to carry out computational experiments. Open Grid Services Architecture Data Access and Integration (OGSA-DAI) is a good candidate to use as middleware providing access to several structured and semi-structured database products through Web/Grid services. The integration technique and its reference implementation described in this paper enable e-Scientists to reach databases via OGSA-DAI within their scientific workflows at run-time and give a general solution that can be adopted by any workflow management system.