Service order provisioning is an important telecommunication application that automates the process of providing telephone services in response to the customer requests. It is an example of a multi-system application that requires access to multiple, independently developed application systems and their databases. In this paper, we describe the design and implementation of a prototype system 1 that supports the execution of the Flexible Transactions and its use to develop the service order provisioning application. We argue that such approach may be used to support the development of multi-system, flow-through processing applications in a systematic and organized manner. Its advantages include fast and easy specification of new services, support for testing of the declaratively specified work-flows, and the specification of potential concurrency among the tasks constituting an application.

In many applications in a multidatabase environment global serializability is needed to assure correctness of concurrent execution of transactions. The serializability of all local schedules is, by itself, not sufficient to ensure the global serializability, since the (relative) local serialization orders of subtransactions of global transactions must be the same at all systems the global transactions execute. In this paper, we present a fully decentralized global concurrency control method in which the concurrency control decisions concerning global transactions can be made at each site, based on the information that is locally available. The method uses a top-down approach to enforce the same serialization order at all sites a global transaction is executed. The proposed method uses forced local conflicts to prevent unacceptable local schedules while assuring deadlock free execution. 1 Introduction A Multidatabase System (MDBS) is a federation of autonomous and possibly heterogeneou...

. Database applications often impose temporal dependencies between transactions that must be satisfied to preserve data consistency. The extant correctness criteria used to schedule the execution of concurrent transactions are either time independent or use strict, difficult to satisfy real-time constraints. On one end of the spectrum, serializability completely ignores time. On the other end, deadline scheduling approaches consider the outcome of each transaction execution correct only if the transaction meets its real-time deadline. In this paper, we explore new correctness criteria and scheduling methods that capture temporal transaction dependencies and belong to the broad area between these two extreme approaches. We introduce the concepts of succession dependency and chronological dependency and define correctness criteria under which temporal dependencies between transactions are preserved even if the dependent transactions execute concurrently. We also propose a chronological s...

Two components of transaction management in multidatabase systems are concurrency control and reliability. Multidatabase systems constructed from autonomous independent database managers are an alternative to homogeneous integrated distributed database systems. Multidatabase transaction management has long been of interest, but general solutions have only recently been forthcoming. Early approaches were either read-only or permitted updates to only one of the underlying databases at a time, required modification to the underlying database systems, or suggested that the DBMS scheduler be replaced with another which controlled transactions from "above". The most pessimistic scenario is assumed in this research where the individual database managers of the multidatabase system are totally autonomous. The work contributes first by demonstrating the importance of and provide a formal model for multidatabase systems. The formalism is capable of capturing the issues related to both concurrenc...

Abstract. The integration of heterogeneous database environments is a difficult and complex task. The A la carte Framework addresses this complexity by providing a reusable and extensible architecture in which a set of heterogeneous database management systems can be integrated. The goal is to support incremental integration of existing database facilities into heterogeneous, interoperative, distributed systems. The Framework addresses the three main issues in heterogeneous systems integration. First, it identifies the problems in integrating heterogeneous systems. Second, it identifies the key interfaces and parameters required for autonomous systems to interoperate correctly. Third, it demonstrates an approach to integrating these interfaces in an extensible and incremental way. The A la carte Framework provides a set of reusable, integrating components which integrate the major functional domains, such as transaction management, that could or should be integrated in heterogeneous systems. It also provides a mechanism for capturing key characteristics of the components and constraints which describe how the components can be mixed and interchanged, thereby helping to reduce the complexity of the integration process. Using this framework, we have implemented an experimental, heterogeneous configuration as part of the object management work in the software engineering research consortium, Arcadia. Key Words. Heterogeneous databases, extensible databases, open architectures,

ahmed8cs.purdue.edu 'This work is supported by a PYI award horn NSF under grant IRI-8857952 A heterogeneous distributed database system (HDDBS) is a system which integrates pre-existing databases to support global applications accessing more than one database. This paper outlines possible approaches to con-curency control in 1LI)DBSs. The top-down approach emerges as a viable paradigm for ensuring the proper concurrent execution of global transac-tions ia an HDDBS. The primary contributions of this paper are the general schemes for local concurrency control wit11 pre-specified global serialization orders. Two approaches are outlined. The first is intended for performance enhancement but violates design autonomy, wbib the second does not vi-olate local autonomy at the cost of generality ( it does not apply to all local concurrency control protocols). This study is intended as a guiding light through the maze of concurrency control in this new environment and

A Scalable Distributed Data Structure (SDDS) stores application data in a file transparently distributed over the nodes of a multi-computer, [LNS93]. The file consists of records identified each by a primary or a k-d key. Each storage node, the server node of the SDDS, stores the record in a bucket. The number of storage nodes, dynamically scales with the file size through the splits of the overloaded buckets. A split typically evacuates half