Nowadays many data grid applications need to manage and process a huge amount of data distributed across multiple grid nodes and stored into heterogeneous databases. Grids encourage the publication of scientific data in a more open manner than is currently the case, and many e-Science projects have an urgent need to interconnect legacy and independently operated databases through a set of data access and integration services. In the data grid area a set of dynamic and adaptive services could address specific issues related to automatic data management aiming at both providing high performance and fully exploiting a grid infrastructure. In this paper we introduce the Grid-DBMS concept, a framework for dynamic data management in grid environments, highlighting its requirements, architecture, components and services.