Definition
A ConTract is an extended transaction model that employs transactional mechanisms in order to provide a run-time environment for the reliable execution of long-lived, workflow-like computations. The focus is on durable execution and on correctness guarantees with respect to the effects of such computations on shared data.
Key Points
The notion of a ConTract (concatenated transactions) combines the principles of workflow programing with the ideas related to long-lived transactions. The ConTract model is based on a two-tier programing approach. At the top level, each ConTract is a script describing a (long-lived) computation. The script describes the order of execution of so-called steps. A step is a predefined unit of execution (e.g., a service invocation) with no visible internal structure. A step can access shared data in a database, send messages, etc.
A ConTract, once it is started, will never be lost by the system, no matter which technical problems (short of a real...
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Recommended Reading
Reuter A. and Waechter H. The ConTract model. In Readings in Database in Database Systems, M. Stonebraker, J. Hellerstein, (eds.). (2nd edn.), Morgan Kaufmann, Los Altos, CA, 1992, pp. 219–263.
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© 2009 Springer Science+Business Media, LLC
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Reuter, A. (2009). ConTract. In: LIU, L., ÖZSU, M.T. (eds) Encyclopedia of Database Systems. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-39940-9_727
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DOI: https://doi.org/10.1007/978-0-387-39940-9_727
Publisher Name: Springer, Boston, MA
Print ISBN: 978-0-387-35544-3
Online ISBN: 978-0-387-39940-9
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