Peter Dadam

Advanced information management (AIM): advanced database technology for integrated applications

The Advanced Information Management (AIM) project is currently one of the main activities at the IBM Scientific Center in Heidelberg. The main purpose of the project is to understand the database requirements and respective solutions for advanced integrated applications such as computer-integrated manufacturing and computer-integrated office. These application areas require an advanced database technology which is able to manage a large variety of data of various types in a consistent and efficient way. The underlying database technology should support not only simple numbers and simple tables used in business administration, but also large complex structured objects, including text, image, and voice data, in a uniform way. This paper describes the background, goals, and accomplishments of the AIM project. It also provides an overview of the design goals, the implementation, and the underlying concepts of AIM-P, an experimental database management system under development in the AIM project.

A lock technique for disjoint and non-disjoint complex objects

Using database systems in the field of non-standard applications like engineering, robotics, etc. leads to many new requirements. Some of the major ones are support of (disjoint and non-disjoint) complex objects and of long transactions. These requirements disclose severe drawbacks of traditional concurrency control techniques: Transactions are either serialized unnecessarily or the concurrency control overhead grows drastically. Furthermore, traditional lock protocols cannot be applied in a straightforward way to non-disjoint complex objects.

The Advanced Information Management Prototype

The Advanced Information Management Prototype is a system that has been designed and implemented as research vehicle for the area of non-standard database applications. It is an object oriented system heavily influenced by the ideas of nested relations (e.g. NF2, VERSO).

Managing Schema Versions in a Time-Versioned Non-First-Normal-Form Relational Database

Support of time versions is a very advanced feature in a DBMS. However, full flexibility of history processing is achieved only if we can also change the database schema dynamically, without touching the history. A technique for achieving this goal is here presented, in the frames of the Non-First- Normal-Form (NF2) relational data model. The environment is a pilot DBMS supporting this model, developed by the Advanced Information Management (AIM) project at the IBM Heidelberg Scientific Center. The technical solution pursues to minimize the storage space and the number of data versions. One way to achieve this is to avoid the immediate update of all data instances in the context of a schema change. Transformations between versions enable the correct interpretation of data. The management of time-related queries becomes complicated, when schema changes are involved. The paper describes a technique of applying global views over different schema versions, when formulating the queries and their results.

Managing Complex Objects in R2D2

R2D2 — A Relational Robotics Database System with Extensible Data Types — is a joint project of the IBM Heidelberg Scientific Center and the University of Karlsruhe, Computer Science Department. It aims at the design and implementation of a data management system to support engineering (esp. robotics) applications. The management of complex objects in R2D2 is supported by the underlying database system AIM-P. In this paper we describe the AIM-P system in some detail, its data model and database language, and we emphasize the aspects of extensibility by user defined data types and functions.

The recovery manager of the advanced information management prototype

Abstract The physical integrity of a database can be violated by many different kinds of software and hardware failures. Well-known examples for these kinds of failures are application program interrupts (e.g. due to a division by 0), system crashes (e.g. due to a power failure), and disk crashes (e.g. due to some kind of mechanical concussion). To restore the database to a consistent state in these and other situations, appropriate database logging and recovery mechanisms must be provided and must be integrated into the Database Management System (DBMS). This paper presents the logging and recovery strategies of the Advanced Information Management Prototype (AIM-P), a DBMS prototype which has been designed and implemented in a research project at the IBM Heidelberg Scientific Center. AIM-P transaction management is heavily based on the use of so-called ‘Transaction-Oriented Work Spaces’ (short TWSs). Each TWS can be seen as a private database partition (segment) where a running transaction can store its modified data before the end of the transaction. The TWS can be used, as we will show, for efficient transaction undo and redo processing in case of a failure. In the present paper, the TWS concept is introduced, its effects on AIM-P transaction management are explained, and its usage for database recovery is outlined.

Sperren disjunkter, nicht-rekursiver komplexer Objekte mittels objekt- und anfragespezifischer Sperrgraphen

Die Benutzung von Datenbanksystemen im Bereich der sogenannten Nicht-Standard-Anwendungen wie etwa CAD/CAM, Robotik und Kunstliche Intel1igenz fuhrt zu zahlreichen neuen Anforderungen. Dazu zahlen vor allem die Verwaltung komplexer Objekte und die Unterstutzung von Workstation-Server-Umgebungen mit den dort vorherrschenden langen Transaktionen. Traditionelle Synchronisationsverfahren fur den Mehrbenutzerbetrieb weisen im Hinblick auf diese Anforderungen gravierende Nachteile auf: Entweder werden Transaktionen, die eigentlich parallel ablaufen konnten, unnotigerweise serialisiert, oder aber der systeminterne Aufwand fur die Mehrbenutzerkontrolle steigt drastisch an, was sich auf das gesamte Systemverhalten einer Anwendung stark leistungsmindernd auswirken kann.

Forschung und Entwicklung im Datenbank-Management-System-Bereich

Datenbank-Management-Systeme (DBMSe) werden schon seit den 60er Jahren im administrativen („kommerziellen”) Bereich auf immer breiterer Basis eingesetzt. Waren die ersten Systeme hinsichtlich ihres Benutzungskomforts sowie der maximal zu speichernden Datenvolumina noch relativ bescheiden, so erlauben heutige, moderne DBMSe die Speicherung sehr groser Datenmengen, ermoglichen konkurrierendes Lesen und Schreiben und bieten einen hohen Grad an Datensicherheit. Auf Grund dieser Eigenschaften ist es nicht verwunderlich, das man DBMSe heute gerne auch in anderen Bereichen einsetzen wurde. Das Spektrum der potentiellen, neuen Anwendungsgebiete ist dabei sehr breit und vielfaltig. Entsprechend breit und vielfaltig sind auch die Forschungs- und Entwicklungs-Aktivitaten im DBMS-Bereich gefachert. Sie reichen von der Weiterentwicklung der „klassischen“DBMS-Architektur, uber die Verteilung des Datenbestandes auf mehrere Rechner (verteilte DMBSe, Mehrrechner-DBMSe, ausfallsichere DBMSe), uber Anwendungen im Ingenieur-Bereich (insbesondere CAD/CAM) bis hin zur Datenverwaltung in Expertensystemen.