Specifying Flexible Tasks in a Multi-database.
Marian H. Nodine, Noela Nakos, Stanley B. Zdonik · 1994
Interactions are open nested flexible transactions used to define long-lived tasks that access multiple heterogeneous databases. Interactions operate on a multidatabase where the local databases are accessed via procedures called steps. The steps in a local database encapsulate its information and allow it to be accessed uniformly. In this paper, we focus on issues of flexible task specification in a multidatabase. We define a language, TaSL, that allows a multidatabase user to define an Interaction to the multidatabase in terms of the steps provided by the local databases. TaSL allows an Interaction definer to specify sequences of steps that should be executed atomically (as classic transactions) in the multidatabase. The user also can specify constraints that must be maintained on the data for the Interaction itself to remain consistent. If these constraints are violated, committed transactions may need to be compensated for, so an alternative execution can be attempted. 1 Introduct...