Regular expression types have been proposed as a foundation for statically typed processing of XML and similar forms of tree-structured data. To date, however, regular expression types have been explored in special-purpose languages (e.g., XDuce, CDuce, and XQuery) with type systems designed around regular expression types "from the ground up." The goal of the Xtatic language is to bring regular expression types to a broad audience by offering them as a lightweight extension of a popular object-oriented language, C#. We develop...

The Tycoon Store Protocol (TSP) specifies a clean interface between the frontend and the backend of fully integrated persistent environments. In contrast to high-level relational or object-oriented database languages, TSP is based on a low level, untyped, but highly flexible tagged store model that is particularly well-suited for the implementation of higherorder persistent polymorphic languages. We describe the TSP operations in some detail and give insight into TSP's design rationale. We also report on the existing set of TSPcompliant backends including TSP adaptors to commercial object stores. A TSP client can choose dynamically between these backends and it is possible to exchange complex object graphs between all TSP-compliant stores via a platformindependent external data representation. 1 Introduction and Motivation Virtually all systems that have to work with large-scale persistent data have a system architecture where there is a clean separation between a frontend performing...

An interesting research area for distributed database systems is inaccessibility. Even if part of the database is inaccessible, a query should be evaluated reasonably. This means, that appropriate rules for propagation and minimization of errors induced by inaccessibility are needed. Furthermore, the result of a query in a distributed database system must be regarded to be potentially vague. In this paper we presentahybrid representation for vague sets, that consists of (1) an enumerating part, whichcontains the elements we could access during query processing, and (2) a descriptive part, which describes the relevant elements we could not access. Further weintroduce propagation rules, which can be used to minimize the vagueness of a query result represented in this hybrid way. Thereby, we propose differentlevels of accuracy for the descriptivepart. As far as weknow this is the first approach using a descriptive part to qualify the missing elements of a result. An example for the usef...

In current enterprises, data is distributed over a multitude of heterogeneous, autonomous database systems. These systems are often isolated and an exchange of data among them is not easy. On the other hand, decreasing time-to-market periods and raising techniques like Concurrent Engineering require good support in dynamic change of data location in various granularities. Data will not reside in the database system of a project group or department all the time but need to be moved or duplicated concurrently to others. To fulfill this industrial requirement, we develop functionality enabling different granularities of data (object) migration among multiple database systems. The underlying architecture and concepts are being derived from a requirement analysis and extend a federated DBS approach. 1 Introduction Database systems are essential components of today's information systems. For more than two decades, different database systems have been built or acquired in the enterprises. D...

This paper investigates the problem of integration between relational and objectoriented databases. We discuss an approach based on class and attribute mappings and show how OQL, the ODMG query language, can be embedded in a set of primitives of a mapping language to serve as a basis for object-relational data integration. We then describe the technique used in the implementation of a prototype built on top of an object-oriented view mechanism, which allows the construction of an object view of a relational database. 1 Introduction Many new applications have to manipulate legacy data (data existing in traditional database systems) in addition to new data manipulated with the support of the new generation of object database systems (ODBMSs). ODBMSs provide advanced technology for complex applications but their use is not yet so widespread. Therefore, the problem is to migrate or integrate these legacy data into object based environments without being forced to redevelop existing applic...

This paper introduces a presentation language for GIS. This language is designed to be used a standalone tool, or in conjunction with a query and manipulation functions. The proposed language is based on an object-oriented data model and on concepts used in the object-oriented query language proposed standard OQL (Object Query Language). The language is part of the SPRING environment, a GIS system which integrates the diverse types of spatial data (cadastral maps, thematic maps, digital terrain models and images).

Advanced multimedia applications call for integrated DBMS support, i.e., the integrated modeling, management, and interactive presentation of persistent multimedia documents. Generic services for the presentation of multimedia documents have to be available at the database clients. This includes continuous data delivery, realization of presentation layout, synchronization enforcement, and an efficient interaction handling. In this paper, we propose a Java application programming interface (Java API) to a multimedia enhanced OODBMS. We follow a two-step approach: First, we implement access to persistent data managed by the core OODBMS. Second, we present the design of generic multimedia presentation services in the Java. This Java API enables database client applications to access and to present multimedia documents persistently stored in the database. With our Java API platform-independent access to multimedia information stored in database systems is possible. 1 Introduction Many Jav...

In the paper, we propose the PLO (Partially Labeled Objects) data model and its application to uniform representation of complex values and semistructuxed data. The model is an extended variant of the well-known OEM data model and allows coexistence of labeled and non-labeled objects. We show that the notion of partially labeled objects is essential in the case of transformation complex values, involving constructions of the type "set of sets", into sets of partially labeled objects. We present algorithms for such transformation.

In this work, a method for generating external schemas in object oriented databases in the ODMG framework is proposed. External schema generation involves obtaining all the relationships existing between the classes selected to make up an external schema. This generation process is part of an external schema definition system that we are developing, which allows the definition of external schemas in ODMG. External schemas generated with this process do not extend the object-oriented paradigm and, the generation of unnecessary intermediate classes is avoided.

Existing federated database systems (FDBS) provide uniform access to multiple heterogeneous DBS, but do not enable objects to move across the DBS while retaining global identity. To fulfill this requirement of industrial users, we incorporate into FDBS a flexible object migration mechanism to move or duplicate objects from one component database system to another. We present different capabilities for "what" and "how" to migrate and consider the migration of both single objects and whole object graphs, i.e. an object together with related objects. 1 Introduction In many enterprises, multiple different database systems have been built or acquired over the last several years. When data communication became easier, the request for coupling databases increased to allow controlled sharing of data. The approach of federated database systems (FDBS) [8, 16] became very important in this field because it retains the autonomy of the multiple existing database systems. The gigabytes of data ins...