We have developed a platform, called Cyclone Database Implementation Workbench (CyDIW), that can be used to implement new database prototypes, use existing command-based systems, and conduct experiments. The workbench allows seamless integration of multiple systems and provides useful services. To support database implementation page-based storage and buffer managers are built-in. A scripting language for batches of commands is included. Experiments are encapsulated as batches of commands on multiple systems. A simple and easy to use GUI is available that acts as an editor and a launchpad for execution of batches of commands. Emphasis in CyDIW is on simplifying the logistics surrounding setting up experiments that are comprehensive and self-contained. The benchmarking services in CyDIW can be used for lightweight benchmarking, where a benchmark consisting of a data set and a suite of commands is given. A benchmarking experiment collects performance statistics from multiple systems based on varying parameters and plots benchmarking results without leaving the GUI. Setup for the system is easy. All configuration settings are recorded in XML documents that are highly portable and readily visible. Once installed, batches representing experiments can be exchanged as text files and executed on CyDIW on any computer.

This paper presents an XML-based approach to implementing the parametric model of temporal databases. In the parametric model, attribute values are functions of time and the entire history of an object is modeled in terms of a single tuple. This property makes it difficult to adapt the parametric model within the conventional databases. However, XML is an attractive option for implementation because data boundaries are not problematic in XML. Native XML storage with pagination is used for storing temporal data and the DOM parser for the paginated XML storage is used for data access. The primitives for the query language are implemented using the DOM parser. Many artifacts, such as parse tree and expression tree are also represented in XML. We hope that this paradigm offers an elegant approach for implementation of complex data models.

Querying object evolution in temporal databases is interesting, but neither SOL-like algebraic languages nor general purpose languages take evolution into account. This paper presents a language, called the Event Matching Language, that is specifically designed for querying object evolution. The language is a pattern matching language based on the concept of cursor borrowed from SNOBOL4.

This paper deals with dimensional data. Examples of dimensions are space and time. Thus, temporal, spatial, spatiotemporal values are examples of dimensional data. We define the notion of dimensional object, extending an object-oriented ODMG-like type system to include dimensional types. We then address the problem of querying dimensional objects. Linguistic constructs are introduced that allow objects with different dimensions to be mixed in the same phrases. This allows the user to formulate both associative and navigational accesses seamlessly without having to worry about the dimensions of the various data elements involved.

This paper presents algebraic identities and algebraic query optimization for a parametric model for temporal databases. The parametric model has several features not present in the classical model. In this model, a key is explicitly designated with a relation, and an operator is available to change the key. The algebra for the parametric model is three-sorted; it includes 1) relational expressions that evaluate to relations, 2) domain expressions that evaluate to time domains, and 3) Boolean expressions that evaluate to TRUE or FALSE. The identities in the parametric model are classified as weak identities and strong identities. Weak identities in this model are largely counterparts of the identities in classical relational databases. Rather than establishing weak identities from scratch, a meta inference mechanism, introduced in the paper, allows weak identities to be induced from their respective classical counterpart. On the other hand, the strong identities will be established from scratch. An algorithm is presented for algebraic optimization to transform a query to an equivalent query that will execute more efficiently.

We propose a pattern matching language for spatio-temporal databases. The matching process in time dimension is based upon the evolutionary nature of time, but in spatial dimension it is based on placement, shape and sizes of regions. The concept of pattern matching introduced in this paper is independent of the choice of the underlying model for spatio-temporal databases. In particular, the pattern matching language seamlessly extends our SQL-like query language ParaSQL for spatio-temporal databases. The pattern matching language would also have application in active databases, because patterns can be used as triggers.

Transaction time is used for time stamping object values to record their database history and formulate a zero information loss model for database transactions. The model consists of three components, a data history store, an update store, and a query store. In such a model, the effect of a past transaction (a query or an update) can be determined at any time. Additionally, the update and query stores make it possible to reconstruct the circumstances of updates and the information divulged in queries. Such a model is suitable for the design of secure, easy-to-audit database systems.>

We propose a generalized relational model for a temporal database which allows time stamping with respect to a Boolean algebra of multidimensional time stamps. The interplay between the various temporal dimensions is symmetric. As an application, a two dimensional model which allows objects with real world and transaction oriented time stamps is discussed. The two dimensional model can be used to query the past states of the database. It can also be used to give a precise classification of the errors and updates in a database, and is a promising approach for querying these errors and updates.

In a temporal database, time values are associated with data item to indicate their periods of validity. We propose a model for temporal databases within the framework of the classical database theory. Our model is realized as a temporal parameterization of static relations. We do not impose any restrictions upon the schemes of temporal relations. The classical concepts of normal forms and dependencies are easily extended to our model, allowing a suitable design for a database scheme. We present a relational algebra and a tuple calculus for our model and prove their equivalence. Our data model is homogeneous in the sense that the periods of validity of all the attributes in a given tuple of a temporal relation are identical. We discuss how to relax the homogeneity requirement to extend the application domain of our approach.

In a conventional database, out of date information is deleted from time to time to keep the database up-to-date. In some applications it is not appropriate to discard old information. In a temporal database, time values are associated with each data item to indicate its period of validity. We propose a model for temporal databases within the framework of classical relational database theory. Our basic model is homogeneous in the sense that the periods of validity of all the attributes in a given tuple of a temporal relation are identical. The model is realized as a temporal parameterization of static relations. The concepts of normal forms, dependencies, etc., can be extended to our model, allowing the proper initial structuring of the database. We develop relational algebra and tuple calculus for our model and prove their equivalence. We generalize the homogeneous model to a multihomogeneous model which allows us to model a significant part of the real world.

In modeling temporal databases, one essentially time stamps all the atomic data elements.As long as this time stamping is not altered, the information

A query language, called HTQCEL. is presented for a model for temporal databases proposed b.y the first author.Z'iime is represented as a sequence of discrete instants.The approach brings temporal databases within the classical framework of relatl'onal databases.1.