Clesio Saraiva dos Santos

TVQL - Temporal Versioned Query Language

The Temporal Versions Model (TVM) is an Object Oriented Data Model developed to store the object versions and, for each version, the history of its dynamic attributes and relationships values. In this work, we propose a query language for this model. The language, called Temporal Versioned Query Language - TVQL, is based on SQL, adding new features to recover temporal information and versions. An alternative to its implementation on top of a commercial database is also presented.

Adding Time to an Object-Oriented Versions Model

In this paper, we propose an object-oriented version model which presents temporal concepts to store not only the object lifetime but also the history of dynamic attributes and relationships defined in the versioned objects and versions. One of the main features of our model is the possibility of having two different time orders, branched time for the object and linear time for each version. The model supports integration with existing databases, by allowing the modeling of normal classes among the temporal versioned classes. Finally, an approach to its implementation on top of a commercial database is presented.

Change Management for a Temporal Versioned Object-Oriented Database

In this paper, we propose a schema versioning mechanism to manage the schema evolution in temporal object-oriented databases. The schema evolution management uses an object-oriented data model that supports temporal features and versions definition – the Temporal Versions Model – TVM. One interesting feature of our proposal is that TVM is used to control not only the schema versioning, but also the storage of extensional database and propagation of the changes performed on the objects. The extensional data level supports integration with the existing database, allowing the maintenance of conventional and temporal versioned objects. The instance propagation approach is proposed through the specification of propagation and conversion functions. These functions assure the correct instance propagation and allow the user to handle all instances consistently in both backward and forward schema versions. Finally, the initial requirements concerning data management in the temporal versioning environment, during schema evolution, are presented.

TVL_SE – Temporal and Versioning Language for Schema Evolution in Object-Oriented Databases

This paper presents a language designed for the description of both temporal schema versioning and schema modification in object-oriented databases. The language supports temporal and versions features in both schemata and data levels. An extension of the ODMG standard is presented in order to incorporate temporal and versioning features into ODL language to properly manage the schema evolution mechanism. Thus, this proposal improves the database environment with temporal and versioning features concerning database modification. The solution to the problem is shown to be feasible since it is defined in terms of the ODMG standard.

Dynamic Schema Evolution Management Using Version in Temporal Object-Oriented Databases

In this paper, an analysis of the schema evolution process in object oriented databases is made using an object oriented data model that supports temporal features and versions definition - the Temporal Versions Model. A meta schema structure is defined to store information concerning to evolutionary schema states, as well as their classes, attributes and relationships. An implementation proposal is presented, combining specification and manipulation mechanisms including version and time concepts. Two alternatives are defined for the database extension management: multi-pool for schema versioning and single-pool for class versioning. Concerning the physical representation, both approaches can be used in the same application.

Modelling an Engineering Design Application Using Extended Object-Oriented Concepts

This paper presents an approach to extend objectoriented data models, in which versions of an object are allowed to appear at dtyferent levels of an inheritance hierarchy, in contrast to the known approaches where they are admitted only at one level. This approach allows the design and instantiation of objects to become very natural, starting with the design of an object in a class and refining it, adding properties to the subclasses. Versions of objects can be defined in a subclass, having ascendant versions/objects associated to the superclasses. The paper also discusses how the extended model can be used to model engineering applications, fulfilling their requirements. The application is the STAR framework, which implements an innovative and flexible data model that allows the user to define an object schema for each design object. Design alternatives and views can be created during the design process and are represented in the object schema. Versioning appears in the STAR model not only for the real design data, but also for alternatives and views in the object schema. This requirement is not naturally modeled by the existing version models in object-oriented databases.

Versions in the context of object-oriented database systems

This paper proposes an integration of the version concept with the abstraction concepts present in object-oriented database models, considering structural aspects. The possible relationships between objects (and versions) and their ascendents in the class or type hierarchies is discussed and a discipline for version creation is proposed, based on the object constructors used to build the versions.

TOWARDS THE AUTOMATED DESIGN OF DATABASE SYSTEMS: APPLICATION TO PRODUCTION MANAGEMENT

The paper presents a method and a set of tools for the automated design of databases for nonconventional applications, based on a conceptual modelling approach, which follows the E-(for Entity) model. The E-model is a semantic data model which accepts a graphical representation, making its use and understanding quite comfortable for practicians of the application. One of the first applications, which also provided many of its functional requirements, is a production management system.