In a class hierarchy, a “role set ” is t,he set of classes where an object may reside simultaneously. A “migration pattern ” is a sequence of role sets. A “migration inventory, ” which is a set, of migrat,ion patterns, is viewed as a dynamic const,raintm on ohjrct migration. A set of transact ious is “sound ” wrt a11 inventory if it. generates only pat.t.t~rns in the invrntory; “complete ” if all pat,terns in the invent,ory can be generated. An initial stucly on characterizing migration inventories of transact,ions is presented. Three update languages are considered: SL which contains five operat,ors, CSL+ which ext rn(ls SL wit.h posit.ivc conditionals, and CSL which allows hot,h positive and negative condit.ionals. Four kinds of invent.orics are studied based on ln~znrss and znj~~,rtl~ntr s/art. It is shown that inventories produced by SL t,ransactions are regular and every regular inventory can be generated by SL transactions. Soundness and complet,eness for SL t,ransactions are decidahlt3. lnvc\llt,orics gpnrrated by CSL (CSL+) t,ra.nsactions arc r.e‘. and every r.e. inventory can be generat,rd by (:SL+ (CSL) transa.ctions under nonimmediate st,art,. It is also show t,hat, every r.e. immediate-start invent,ory can be obtained by a left quotient, of t,he invent,ory of CSL+ (CSL) transactions hy a regular seb. The exact, charact#erizat.ions are open. However, cvrry contrxl-frcr srt can be generat,ed. Soundness and rmllplPt~enms for ($1, (CSL+) t,ransa.ctions are undecidahlr. 1

The specification of a database system consists of the description of its static information structure as well as of its dynamic behaviour. Whereas in classic conceptual database design the main interest was on the static part, specification of database dynamics became an important topic in the last few years.

We present a class of dynamic constraints (DADs) which are of practical interest and allows one to express restrictions such as if some property hold now, then in the past some other property should have been true. The paper investigates in a constructive manner the definition of transaction-based specifications equivalent to DAD-constraint-based specifications.

This paper investigates temporal integrity constraints in valid time databases, i.e. databases that capture the time-varying nature of the part of reality being modeled. We first provide a taxonomy of integrity constraints in (temporal) databases in order to establish a common terminology. The taxonomy identifies two classes of valid time integrity constraints: intrastate and interstate integrity constraints. Intrastate integrity constraints result from generalizing nontemporal integrity constraints. They guarantee the consistency of every snapshot of a valid time database. Interstate integrity constraints relate and constrain different valid time snapshots and, therefore, they are unique to the temporal dimension. ChronoLog, a query language based on first order predicate logic, can express both types of integrity constraints. Furthermore, timerestricted integrity constraints may be expressed in ChronoLog. Finally, we discuss the efficient checking of valid time integrity c...

Some temporal query languages work directly on a timestamp representation of the temporal database, while others provide a more implicit access to the flow of time by means of temporal connectives. We study the differences in expressive power between these two approaches. We first consider first-order logic (i.e., the relational calculus). We show that first-order future temporal logic is strictly less powerful than the relational calculus with explicit timestamps. We also consider extensions of the relational calculus with iteration constructs such as least fixpoints or while-loops. We again compare augmentations of these languages with temporal left and right moves on the one hand, and with explicit timestamps on the other hand. For example, we show that a version of fixpoint logic with left and right moves lies between the explicit timestamp versions of first-order and fixpoint logic, respectively. 1 Introduction A simple, natural and common way of representing a tempo...

The maintenance of semantic integrity has been recognized as a cornerstone issue for the development of databases and knowledge bases alike. Despite the extensive research conducted during the last two decades, semantic integrity maintenance has yet to become a practical technology. Furthermore, the need for modeling evolving domains has given rise to challenging research issues relating to the incorporation of time in knowledge bases. In this thesis, we study the problem of maintaining the integrity of temporal deductive knowledge bases. We argue that existing approaches in either temporal or deductive databases do not address the problem in a satisfactory manner, nor do they deal with all the issues involved in a unified framework. At first, we propose an assertion language that permits us to express different types of temporal assertions that are not expressible in other formalisms. We define the notion of temporal constraint satisfaction in a bitemporal context. We then follow two ...

This paper presents the extension of integrity constraint mechanisms for maintaining consistency in temporal databases, when both transaction time and valid time are taken into account. This work is based on the database version model, in which consistency is maintained using adequate integrity constraints called mv-constraints. The issue of describing and classifying temporal constraints and the issue of defining them on top of the database version model, by mapping them to mv-constraints, are both addressed. Keywords : temporal database, versions, consistency, integrity constraints. Introduction The work presented here is at the conjunction of three database areas: integrity constraints, temporal data models and versions. Integrity constraints are traditionally used to enforce the accuracy of a database and the modeled reality [GA93]. Temporal data models have been introduced because in many database applications temporal dimensions must be considered, and time must be stored in t...