Wolfgang Käfer

TSQL2 language specification

This docuinent specifies a temporal extension to the SQL-92 language standard. The language is designated TSQLZ. The document is organized as follows. The next section indicates the starting point of the design, the SQL92 language. Section 4 lists the desired features on which the TSQL2 Language Design Committee reached consensus. Section 5 presents the major concepts underlying TSQL2. Compatibility with SQL-92 is the topic of Section 6. Section 7 briefly discusses how the language can be implemented. Subsequent sections specify the syntax of the language extensions.

Mapping a version model to a complex-object data model

The authors present a version model for CAD purposes and its implementation on the basis of a complex-object database management system. The functionality of the model is illustrated with the help of a VLSI design example. In contrast to similar solutions based on the relational data model, this approach allows for a simple and efficient implementation of the version model, allowing for powerful retrieval operations. Sharing of data, which occurs necessarily among versions, is system controlled. This prohibits redundant storage of data. It is concluded that implementing a complex-object database system supporting versions is not more complicated than implementing a complex-object database system without version support.<<ETX>>The authors present a version model for CAD purposes and its implementation on the basis of a complex-object database management system. The functionality of the model is illustrated with the help of a VLSI design example. In contrast to similar solutions based on the relational data model, this approach allows for a simple and efficient implementation of the version model, allowing for powerful retrieval operations. Sharing of data, which occurs necessarily among versions, is system controlled. This prohibits redundant storage of data. It is concluded that implementing a complex-object database system supporting versions is not more complicated than implementing a complex-object database system without version support. >

Realizing a temporal complex-object data model

Support for temporal data continues to be a requirement posed by many applications such as VLSI design and CAD, but also in conventional applications like banking and sales. Furthermore, the strong demand for complex-object support is known as an inherent fact in design applications, and also emerges for advance “conventional” applications. Thus, new advanced database management systems should include both features, i.e. should support temporal complex-objects. In this paper, we present such a temporal complex-object data model. The central notion of our temporal complex-object data model is a time slice, representing one state of a complex object. We explain the mapping of time slices onto the complex objects supported by the MAD model (which we use for an example of a non-temporal complex-object data model) as well as the transformation process of operations on temporal complex-objects into MAD model operations. Thereby, the basic properties of the MAD model are a prerequisite for our approach. For example, time slices can only be directly stored, if non-disjunct (i.e. over-lapping) complex objects are easily handled in the underlying complex-object data model.

A TSQL2 tutorial

This tutorial presents the primary constructs of the consensus temporal query language TSQL2 via a media planning scenario. Media planning is a series of decisions involved in the delivery of a promotional message via mass media. We will follow the planning of a particular advertising campaign. We introduce the scenario by identifying the marketing objective. The media plan involves placing commercials, and is recorded in a temporal database. The media plan must then be evaluated; we show how TSQL2 can be used to derive information from the stored data. We then give examples that illustrate storing and querying indeterminate information, comparing multiple versions of the media plan, accommodating changes to the schema, and vacuuming a temporal database of old data.

Controlling cooperation through design-object specification-a database-oriented approach

The authors propose an operational framework for supporting cooperative design processes carried out by a group of designers. Besides the cooperative refinement of the design-object specification, the introduced cooperation protocol allows cooperative design by system-controlled interchange of design object versions. The versions reflect the process of step-wise improving the design object so as to meet finally its specification. The authors introduce a data integrated design environment based on a nonstandard database system in order to manage the whole cooperation process, i.e. the design objects, the versions, and the design activities.<<ETX>>

Ein Client/Server-System als Basiskomponente für ein kooperierendes Datenbanksystem

Konventionelle Datenbanksysteme besitzen erhebliche Leistungsschwachen bei der Abarbeitung aufwendiger Verarbeitungsalgorithmen auf komplexen Datenstrukturen. Ein Losungsansatz wird in der “semantischen Dekomposition”, also der Zerlegung einer einzelnen komplexen Datenbankoperation in logisch unabhangige Teilschritte, gesehen. Unter Berucksichtigung der Operationssemantik konnen die unabhangigen Teilschritte parallel abgewickelt werden, wodurch insgesamt eine Reduktion der Antwortzeit erwartet wird. Die praktische Erprobung und Validierung dieses Ansatzes erfordert die Entwicklung eines verteilten, kooperierenden Datenbanksystems.

A Second Example

This chapter expresses the schema and some of the queries of the extensive consensus test suite for temporal relational query languages [Jensen 1993]. The test suite is not related to performance issues, but has a semantic focus and is intended to be an aid in evaluating the user-friendliness of temporal query languages. An attempt is made to express the schema and queries in TSQL2 in a convenient and natural fashion, as an informal evaluation of that language’s user-friendliness.

Flexible Entwurfsdatenverwaltung für CAD-Frameworks: Konzept, Realisierung und Bewertung

Eine der Hauptzielrichtungen von CAD-Frameworks ist die Integration von einzelnen, eigenstandigen CAD-Werkzeugen mittels einer zentralen Datenverwaltung. Wesentliche Aufgaben hierbei sind die Verwaltung aller entwurfsrelevanten Daten sowie die effiziente Bereitstellung werkzeugrelevanter Daten fur den werkzeugspezifischen Entwurfsschritt. Hierzu sind die vom jeweiligen Werkzeug zu bearbeitenden Entwurfsdaten bzw. Entwurfsobjekte zu selektieren und in der jeweils benotigten Form bereitzustellen. Nach Beendigung des Entwufsschrittes sind die geanderten Daten in den aktuellen Datenbestand zu integrieren. Um diese schwierige Aufgabe meistern zu konnen, ist es notig, die vorherrschenden Objekt- und Entwurfsstrukturen entsprechend zu berucksichtigen.

PRIMA - a database system supporting dynamically defined composite objects

PRIMA is a non-standard database system developed at the University Kaiserslautern. Its major purpose is the support of engineering design applications, such as VLSI design and software engineering. The applications require tailored application-dependent interfaces which, however, all share basic notions like that of a composite object. Hence, the approach of PRIMA is to offer an application-independent complex-object interface (the moleculeatom data model, shortly called MAD model) and to provide means to easily augment this interface by application-dependent functionality. In the following, we will concentrate on the MAD model and its implementation.

Messen und Bewerten paralleler Client/Server-Architekturen - am Beispiel des kooperierenden Non-Standard-Datenbanksystems PRIMA

Mit der stetigen Verbreitung und Vernetzung von Arbeitsplatzrechnern sowie dem wachsenden Einsatz von Mehrrechnersystemen gewinnen auftragsorientierte Systemmodelle, die eine Zerlegung in auftraggebende und auftragnehmende Systemkomponenten vorsehen, zunehmend an Bedeutung. Die effektive Nutzung der verteilten Rechnerleistung erfordert geeignete Masnahmen zur Unterstutzung der parallelen Auftragsabwicklung. Neben Konzepten zur Betriebssystemeinbettung adaquater Ablaufumgebungen existiert ein Bedarf an Mesweikzeugen und Analysemethoden, die eine quantifizierbare Bewertung paralleler, auftragsorientierter Anwendungssysteme erlauben.