W. Kafer, H. Schoning, Realizing a Temporal Complex-Object Data Model, in: Proc. of the 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... to represent and manage the history of data objects (extensional properties) the introduction of temporal schema versioning enables one to represent and manage the history of the structure of data objects (intensional properties) Whereas a great deal of research work was done on temporal OODBs [11, 12, 13, 14, 15], temporal schema versioning has been deeply investigated so far only for the relational model [16, 17] In this paper, we deal with the introduction of temporal schema versioning in an object oriented database, also taking into account formal aspects. Within the object oriented framework, ....

W. Kafer, H. Schoning, Realizing a Temporal Complex-Object Data Model, in: Proc. of the 1992.

....a classical example through typical temporal queries. Section 5 reports on the prototype development. Section 6 concludes the paper and sketches future work. 2 Related work In the object oriented approaches (see [20] for a survey) temporal dimensions can be defined at the object level (e.g. TMAD [14], OSAM T [22] or at the attribute level (e.g. TOOSQL [16] OOTempSQL [6] TF ORM [10] T Chimera [2] or at both levels (e.g. TIGUKAT [12] OODAPLEX [26] Some of these studies support only a single time dimension (valid or transaction time) others support bitemporal time. Depending of the ....

W. Kafer and H. Schoning. Realizing a temporal complex-object data model. In Proc. of the ACM SIGMOD Conference, California, June 1992.

....object data models. The research on temporal models has generally followed this trend. Temporal object models can more accurately capture the semantics of complex objects and treat time as a basic component. There have been many temporal object model proposals (for example, RS91,SC91,WD92,KS92,CITB92,BFG97] These models differ in the functionality that they offer, however as in relational systems, they assume a set of fixed notions of time. Wuu Dayal [WD92] provide an abstract time type to model the most general semantics of time which can then be subtyped (by the user or database ....

....needs. The third objective is to show how the various existing temporal object models can be represented within this framework. The final objective is to use the framework to analyze and compare the different temporal object models based on the design dimensions. In particular, the [RS91,SC91,KS92,PM92,CITB92,BFG97] temporal object models are considered. The work of Wuu Dayal [WD92] and Cheng Gadia [CG93] which follows a similar methodology as [WD92] are not considered since they do not provide concrete notions of time in their models. Object models which support versioning using ....

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W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, June 1992.

.... 2 1 2 2 1 2 valid transaction temporal immutable non temporal migration oo data time time values class model structure dimension objects features [21] OODAPLEX user defined arbitrary objects NO [6] OODAPLEX linear valid objects NO [11] TIGUKAT user defined valid objects NO [13] MAD linear valid objects NO [19] OSAM linear valid objects NO [15] 3DIS linear valid objects NO [7] generic linear valid objects NO Our model Chimera linear valid both YES Legenda: One single time dimension is considered, but it can be interpreted either as transaction or as valid time. ....

.... Chimera data model attributes operations what temporal kinds histories is attribute of of object timestamped values attributes types [21] arbitrary functions temporal YES immutable [6] attributes functions temporal NO immutable [11] arbitrary sets of temporal YES pairs immutable [13] objects atomic temporal NO valued immutable [19] objects atomic temporal NO valued immutable [15] attributes sets of temporal NO triples [7] attributes functions temporal YES immutable temporal Our model attributes functions immutable YES non temporal Legenda: With the term ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In M. Stonebraker, editor, , pages 266--275. ACM Press, 1992.

....behavior B calElements returns a list of the calendric elements in a time instant. For example, B calElements applied to the instant June 15, 1995 returns the list (414; 6; 15) 6 Related Work Although there have been a substantial number of proposals on adding time to object models [RS91, RS93, KS92, WD92, DW92, SC93, CG93] it is quite surprising to note that none of them provides comprehensive support for modeling multiple calendars and handling multiple granularities. Most of these models assume the presence of an underlying calendar (usually Gregorian) which has 32 T instant B less: T ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, 1992.

....T 2 1 2 1 2 2 Related works 2. Related works (i) ii) iii) valid oo data time time values class model structure dimension objects features [CC88] generic linear, discrete valid objects NO [CG93] OODAPLEX linear, discrete valid objects NO [GO93] TIGUKAT user defined valid objects NO [KS92] MAD linear, discrete valid transaction objects NO [PM92] 3DIS linear, discrete valid objects NO [RS91] generic linear, discrete valid transaction objects NO [SC91] OSAM linear, discrete valid objects NO [WD93] OODAPLEX user defined arbitrary objects NO Our model Chimera linear, discrete ....

.... data model primitives complex identity what temporal kinds histories is attribute of of object timestamped values attributes types [CC88] attributes functions temporal YES immutable [CG93] attributes functions temporal NO immutable [GO93] arbitrary sets of temporal YES pairs immutable [KS92] objects atomic temporal NO valued immutable [PM92] attributes sets of temporal NO triples [RS91] attributes sequences of temporal NO tuples immutable [SC91] objects atomic temporal NO valued immutable [WD93] arbitrary functions temporal YES immutable temporal Our model attributes ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In M. Stonebraker, editor, , pages 266--275. ACM Press, 1992.

....two different approaches to implement T Chimera in Ode. In this section we analyze and compare the proposed implementations. Moreover, we compare our approaches with two implementation approaches proposed in the literature: the one of Steiner and Norrie [27] and that of Kafer and Schoning [19, 20, 21]. Though for other temporal objectoriented models prototypal implementations have been developed [18, 24] not enough details of such implementations are available to allow an in depth comparison with ours. 9.1 Comparison between our Approaches The first implementation approach is based on the ....

....allows no more modifications on it, need to be supported. 9.3 Comparisons with the Implementation Approach of Kafer and Schoning In this subsection we examine the temporal data model TMAD and its implementation, and we compare it with our implementations. The main objective of Kafer and Schoning [19, 20, 21] is to show that a complex object data model is an appropriate means for handling temporal data. In particular, they explain the mapping of time sequences onto recursively structured complex objects and they show how operations on temporal data can be transformed into complex object operations. ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In M. Stonebracker editor, Proc. of the ACM SIGMOD Int'l Conf. on Management of Data, pages 266-275, ACM Press, 1992.

....how OMS Java has been extended to support the Temporal Object Data Model TOM [SN97c, SN97a] 5. 1 The Temporal Object Data Model TOM TOM is based on the generic object data model OM [Nor93] and exhibits many of the features found in various temporal object oriented models, e.g. RS91, WD93, KS92, BFG96] but in a more generalized form. For example, we timestamp not only data values, but also collections of objects and the associations containing the temporal relationships between objects. Anything considered to be an object in our model may be timestamped, even metadata such as ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In SIGMOD Conference 1992, pages 266--275, 1992.

....of time in TIGUKAT establishes a natural foundation for keeping track of the changes to the schema. This allows applications, such as CAD, to trace their design over time and make revisions, if necessary. There have been many temporal object model proposals (for example, RS91, SC91, WD92, KS92, CITB92, BFG96] In handling temporal information, these models have focussed on managing the evolution of real world entities. The implicit assumption in these models is that the schema of the object database is static and remains unchanged during the lifespan of the object database. More ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, 1992.

....and absolute) keys. Finally, some models keep track of the dynamic links between an object and its most specific class. Indeed, an important dynamic aspect of object oriented databases is that an object can dynamically change type, by specializing or generalizing its current one. 7] 8] 9] [10] [11] 15] 18] 14] Ours o o data Oodaplex generic Tigukat MAD generic OSAM Oodaplex OM ODMG model time linear linear user def. linear linear linear user def. linear linear structure discrete discrete discrete discrete discrete discrete discrete time valid valid valid valid valid valid ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In M. Stonebraker, editor, Proc. of the ACM SIGMOD Int'l Conf. on Management of Data, pages 266--275. ACM Press, 1992.

.... OODAPLEX [228] arbitrary arbitrary OODAPLEX OSAM T [206] valid N A OSAM T OVM [103] transaction identifier OVM Postgres [205] transaction interval Postgres [172] arbitrary arbitrary Sciore 1 [173] both chronon Sciore 2 TEDM [41] valid N A TEDM TIGUKAT [68] both identifier TIGUKAT TMAD [104] valid N A TMAD Temporal [163] both temporal TOODM Object Oriented element Data Model Table 2: Temporal object oriented data models Single chronon Interval Valid time Element (pair of chronons) set of chronons) Time stamped ADM Bassiouni Bhargava attribute Caruso Gadia 2 Gadia 1 values ....

....Based On Impl. Underlying Data Model Algebra MATISSE [4] MATISSE SQL p OODAPLEX [228] OODAPLEX DAPLEX [50] OSQL [20] IRIS SQL p OQL [103] OVM SQL p OQL T [206] OSAM T OSAM OQL TA algebra Orion [111] Kim SQL p PICQUERY [31] TEDM PICQUERY p Postquel [205] Postgres Quel p TMQL [104] TMAD SQL TQL [156] TIGUKAT SQL p TOOSQL [165] TOODM SQL p [164] TOSQL [163] TOODM SQL [164] VISION [34] Caruso meta functions p [172] Sciore 1 annotations [173] Sciore 2 EXTRA EXCESS [32] Table 6: Temporal object oriented query languages based are identified in the third and fourth ....

Kafer, W., and Schoning, H., "Realizing a Temporal Complex-Object Data Model", in Proceedings of the ACM International Conference on Management of Data, pp. 266--275, 1992.

....versions of T. That way, the implementation of a temporal type is actually the implementation of the OQL parameterized object class Temporalh T i. The query language of a temporal OODB must support many different types of temporal queries, including temporal projection and coincidence queries [9]. The most difficult task in expressing temporal queries is event synchronization, mostly found in coincidence queries. For example, inquiring about the salary of the head of a department at some point in time, is requesting to synchronize the temporal attribute, head, of the department with the ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proceedings of the ACM-SIGMOD InternationalConference on Management of Data, San Diego, California, pp 266--275, June 1992.

....sense are managed, but objects in general, which includes things such as code in addition to data. reasonably conclude that he died sometime between 5 : 00am May 30 and 5 : 59am May 30. There have been many object oriented temporal model proposals (see, for example, KC86, RS91, RS93, KS92, DW92, WD92, SC93, CG93] These models differ in the functionality that they offer, but none of them provides support for uniformly handling different domains of time, granularities and indeterminate temporal information. In this paper we describe a temporal object model which is sufficiently ....

....T discreteInterval T discreteDeterminateInterval T discreteIndeterminateInterval T discreteInstant T discreteDeterminateInstant T discreteIndeterminateInstant T specialInterval T span T discreteSpan T granularity Figure 8: The complete time type hierarchy. KC86, RS91, RS93, KS92, WD92, DW92, SC93, CG93] none of them provides support for handling both the continuous and discrete time domains, multiple granularities and indeterminate temporal information. In the context of OBMSs, KC86] describes a model to handle complex objects and discusses the representation and ....

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W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, 1992.

....Complete object coercion can be done by explicitly coercing all the behaviors of an object. Substantial research has been ongoing in the past decade to support the notion of time in various systems [Soo91, TCG 93] Time has been introduced recently in the context of object models [RS91, KS92, DW92, WD92] These studies have concentrated on extending the object model to facilitate various notions of time. Furthermore, query models have been extended by adding new operators and constructs that range over time values and allow for the execution of queries on temporal and non temporal ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. of the ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, June 1992.

....Special Issue on Time Oriented Systems in Medicine The number of patients in treatmentA is the cardinality of the collection returned as a result of the treatmentA.B patients behavior application. 2 5 Related Work There have been many object oriented temporal model proposals (see, for example, [20, 24, 25, 17, 29, 12, 3, 28, 2]) These models differ in the functionality that they offer, but none of them provide support for all the requirements of a pharmacoeconomics medical trial. More specifically, in our model: ffl Both linear and branching orders are supported. The above temporal ODBMSs support only linear time. As ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, 1992.

....(e.g. Gad88, Tan86] might be applied. In the case of temporal object data models, there are three major possibilities. Firstly, timestamping may at the attribute (as in [RS91] or object level. Secondly, if timestamping is at the object level, it may be either at the type level (as in [KS92] in which case a special temporal attribute is included, or at the identifier level, in which case a special temporal object identifier is used. We advocate the use of temporal object identifiers and adopt these in our temporal object model, TOM. However, in existing OODBMS, object timestamping ....

....object model and then, by means of examples, introduce the system and its query language. Our temporal object data model, TOM, is based on the generic object oriented data model, OM [Nor93] and exhibits many of the features found in various temporal object oriented models, e.g. RS91, WD93, KS92, BFG96] but in a more generalized form, as we will demonstrate in this paper. The OM model strictly separates typing from classification in such a way that classification structures model the roles of objects rather than their representation. Classifications are represented by the bulk type ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In SIGMOD Conference 1992, pages 266--275, 1992.

....time domain is used to model time. Timestamps can be either time instants or time intervals. For every time varying attribute in a class, a corresponding subclass is defined to represent the time sequence [SS87] history) of that attribute, thus resulting in a large number of classes. In [KS92] a state of a complex object is represented by the notion of a time slice which basically comprises of a time interval and the object which was valid during the interval. It is not clear however, how other timestamps and domains of time are supported for different applications and whether ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, 1992.

....a natural foundation for keeping track of the changes to the schema. This allows applications, such as CAD, to trace their design over time, make revisions if necessary, and execute historical queries. There have been many temporal object model proposals (for example, RS91, SC91, WD92, KS92, CITB92, BFG97] In handling temporal information, these models have focussed on managing the evolution of real world entities. The implicit assumption in these models is that the schema of the object database is static and remains unchanged during the lifespan of the object database. More ....

W. Kafer and H. Schoning. Realizing a Temporal Complex-Object Data Model. In Proc. ACM SIGMOD Int'l. Conf. on Management of Data, pages 266--275, June 1992.

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