Bruno Defude

Integrated Tools for Object Oriented Persistent Application Development

This paper presents the main characteristics of an integrated environment for object oriented, persistent application development. We first discuss the rationale of our approach and give our analysis of current database systems or persistent languages. Using such systems or languages is still a very difficult task because persistent application development combines the complexity of database schema design together with a software engineering problem.

Consistency Checking in Object Oriented Databases: a Behavioral Approach

This paper presents a mechanism to enforce consistency in object oriented DBMS using pre-conditions and post-conditions on methods. This mechanism is coupled with an exception mechanism to allow deferred controls and semantic tolerance. Conditions are defined using SQL-like expressions and methods composition. A prototype which has been implemented on the O2 object oriented database management system (DBMS) is also described in this paper.

Integrity checking for nested transactions

The authors present a mechanism to specify and to validate consistency constraints in object oriented databases. Constraints are specified using preand post-conditions associated with an exception handling mechanism. During transaction run-time, they treat exceptions corresponding to errors (in this case, they use immediate exceptions which are processed immediately) or presumption of errors (in this case, they use deferred exceptions which are processed at the end of the transaction), in order to insure validation. To refine their mechanism, we enlarge it to nested transactions. Deferred exceptions can be processed at each node of the transaction tree. Using a predefined exception, they propagate an abort of a sub-transaction to its parent transaction. Thus, the parent transaction can choose among different policies for processing the sub-transaction abort.

A Terminological Canonical Data Model for Cooperating Heterogeneous Geographical Information Systems

The best way to make cooperate heterogeneous GIS (Geographical Information Systems) is to integrate them through a federated architecture. This last one necessitates in its first step the definition of a Canonical Data Model (CDM). The GEOgraphical COOPerative Model (GEOCOOPM) we have defined belongs to the family of terminological systems also known as description logics. We develop, in this paper, a precise syntax and semantic of Geocoopm and demonstrate the following: (1) First, Geocoopm gives a semantic to the spatial dimension. (2) It also permits the definition of heterogeneous data types (maps, numerical data, spatial data). (3) Geocoopm can represent various transformations on these data. (4) Finally, it provides a great facility for a good organisation of data and transformations using the subsumption function which enables building many hierarchies of data and transformations. This is a first step towards the schema integration process. We provide many examples to illustrate our claims.

Cluster Entries for Semantic Organization of Peer-to-Peer Network

Techniques of pure flooding queries through a peer-to-peer network[1] reach their limits for data localization which are not replicated and stored through a high number of nodes. To improve implicitly the query routing towards relevant nodes in order to smartly recover all the relevant data, we propose to organize a peer-to-peer network in which the logical neighborhood of each node is built according to the semantic of its content. Indeed, the data we target, are semantically rich, easily classifiable with a field of interest, or a theme (e.g. “rock”, “jazz”, ...in music, or “hydrology”, “oceanography”,...in sciences of environment). The motivation of our approach is based on the fact users/providers query the network on the theme of the data they store. Thus, if a node contains many data about the theme “Hydrology”, the query propagation is more efficient, if the neighbors of this node contain data about “Hydrology”. In the prototype VENISE (serVicE for Node Insertion in Semantic clustErs), we propose a protocol of node insertion based on cluster entries to cluster a peer-to-peer network.

From a Passive to an Active Database Supporting Exceptions

This paper presents a mechanism to enforce consistency in object oriented DBMS using pre-conditions and post-conditions on methods. This mechanism is coupled with an exception mechanism to allow deferred controls and semantic tolerance. Conditions are defined using SQL-like expressions and methods composition. Exceptions are defined at the class level. We consider that an exception has a signature (the context of the exception) and an implementation (the process associated with the exception). We define the semantics of inheritance related to exceptions. The process control of this exception mechanism is also presented. This model can be considered at an execution level and we show how some general integrity rules (e.g referential integrity) can be compiled into pre(post)-conditions and exceptions.