O. Shmueli and A. Itai. Maintenance of views. In Proc of the 1984 ACM SIGMOD Intl. Conference on Management of Data, pages 240--255. ACM Press, 1984.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....sniffing. This process identifies (a) a mapping between cached results and the corresponding queries used to generate those results and (b) a mapping between the queries and the data changes that affect these queries. The second problem is closely related to the prob lem of view maintenance [4, 5, 6, 7] in the context of materialized views in data warehouses. Since a data warehouse consists of a large view, the main fo cus of the database research has been to maintain materialized views incrementally. Numerous algorithms have been proposed for incremental view main tenance [8, 9, 10, 11, 12] ....

O. Shmueli and I. Itai. Maintenance of Views. In ACM $IGMOD, 1984.

....have been developed. Most of them are designed for a traditional, centralized database environment, where it is assumed that view maintenance is performed by a system that has full control and knowledge of the view definition, the base relations, the updated tuples, and the view [HD92,QW91,SI84] These algorithms differ somewhat in the viewdefi they handle. For example, BLT86] considers select project join (SPJ) views only, while algorithms in [GMS93] handle views defis by any SQL or Datalog expression. Some algorithms depend on key information to deal with duplicate tuples [CW91] ....

O. Shmueli and A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD International pages 240--255, Boston, Massachusetts, May 1984.

....with only with mechanism questions concerning materialized sample views. The basic idea of this chapter is to reuse the maximal portion of the original sample when constructing the updated sample. These results are thus a synthesis of classical techniques for updating materialized views [SI84, BLT86, TB88, Han87b, CW91] with the algorithms I have described for sampling from relations and queries. Devroye [Dev91] discusses a similar idea of sample reuse (coupled samples) in a simulation setting. Sample reuse is the basis of panel surveys which are widely used for longitudinal studies. ....

Oded Shmueli and Alon Itai. Maintenance of Views. In ACM SIGMOD International Conference on the Management of Data, pages 244--255, June 1984.

....also. Work mainly focused on incremental view maintenance which only computes a part of view changes to update its materialization in response to changes to the base data. With respect to the websites refresh, we not only desire a perfect incremental view maintenance algorithm for a single view [13, 19, 25, 26, 9] but also aim to achieve a satisfactory of timing constraint with the refresh requirement of a set of views. This timing requirement, never raised in traditional view maintenance where assuming that the maintenance could be completed before the next update of the base data, is especially crucial ....

O. Shmueli, A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD International Conference on Management of Data, pages 240-255, Boston, Massachusetts, May 1984.

....knowledge, that incorporates this optimization. The query language of RHODES is relational algebra extended to be consistent with SQL semantics. Most research in incremental view maintenance assumes that relations are sets and do not have duplicates [BCL89, BLT86, BC79, CW90, CW91, DT92, Kuc91, SI84, UO92, WDSY91] However, most database systems use multisets (sets with duplicates) because many database applications require aggregation and duplicates are necessary for correctly computing aggregate functions. Another reason for the use of duplicate semantics is that duplicate elimination is ....

....requires all intermediate results computed during the view computation to also 2 For definitions of stratified negation and aggregation, refer to Ullman [Ull88] and Mumick et al. MPR90] Chapter 2. A Survey on View Maintenance: Applications and Techniques 18 be materialized. Shmueli and Itai [SI84] also use multiplicity counters for the number of different derivations of a tuple but they use specialized data structures to support them. For instance, each tuple in the database contains pointers to all tuples derived from it. Nicolas and Yazdanian [NY83] use counts to reflect some types of ....

O. Shmueli and A. Itai. Maintenance of Views. In Proceeding of ACMSIGMOD Conference on Management of Data, pages 240--255, 1984.

....of computations, by computing the increment from the result of one computation to the next, are often referred to as incremental computations. Incremental computations are used in database systems in several areas, such as view maintenance [BCL89, BLT86, CW91, DT92, GKM92, GMS93, NY83, Rou91, SI84] reasoning about changes [Kuc91, UO92] integrity constraint verification [CW90, Ple93] alerting [BC79] and active database systems [BA93, GJS92] More remote work on incremental techniques includes work on distributed computing [AISN90, Ita91, WDSY91] programming languages [SH91, TR81] ....

O. Shmueli and A. Itai. Maintenance of Views. In Proceeding of ACM-SIGMOD Conference on Management of Data, pages 240--255, 1984.

....environment is one of the important issues of data warehousing [GM95, Wid95, WB97, GMLWZ98] Initially, some research has studied incremental view maintenance assuming no concurrency. Such algorithms for maintaining a data warehouse under source data updates are called view maintenance algorithms [SI84, BLT86, GMS93, QW91, CGL 96, GL95, LMSS95] There has also been some work on maintaining materialized view de nitions under IS schema changes [LKNR99a, LKNR99b] and on adapting its view extent under IS schema changes [GMR95, MD96, GMR97, NR99, ZR00] Self Maintenance [AJR97, GJM96, QGMW96] ....

O. Shmueli and A. Itai. Maintenance of views. In Proceedings of SIGMOD, pages 240-255, 1984.

....have to be considered, and unless c is kept small, the effort involved in simply bounding the search could become significant. 6. 3 Incremental Changes Whenever some derived information is materialized, a change in the base information needs to be reflected in a change in the derived information [9, 15, 18, 28]. We require precomputed shortest distances between domain centers, and between each domain center and its constituent nodes. Whenever a modification is made to the original graph, this precomputed information has to be updated. Obviously, a complete recomputation would be extremely expensive. One ....

O. Shmueli and A. Itai, "Maintenance of Views," Proc. ACM-SIGMOD 1984 Int'l Conf. Management of Data, Boston, Massachusetts, June 1984, pp. 240-255.

....changes that must be made to the view, given the changes to the base relations and the expression that defines the view. The problem of finding such changes to the views based on changes to the base relations has come to be known as the view maintenance problem, and has been studied extensively [27, 4, 3, 6, 7, 14, 29, 12, 5, 18, 26]. The name is slightly misleading since, as a reading of this literature will indicate, any solution to the problem is applicable in a large number of practical problems, including integrity constraint maintenance, the implementation of active queries, triggers and monitors. Most of the work on ....

O. Shmueli and A. Itai. Maintenance of views. SIGMOD Record 14 (1984), 240--255.

....can lead to significant improvement in run time efficiency; and ffl the implementation of the entire framework that includes both the evaluation and partial instantiation phases. Excellent work has been done on incremental view maintenance for relational, active and deductive databases [5, 6, 9, 11, 13, 14, 21, 23]. Most relevant to our work here are the proposals for deductive databases. 14] deals with recursive views; 11] is concerned with right linear chains; 23] focuses on rules with negations; and last but not least, 13] handles rules with aggregations, recursions and negations. However, all these ....

O. Shumeli and A. Itai. (1984) Maintenance of Views, Sigmod Record, 14, 2, pp 240-- 255.

....views considered, upon the resources used to maintain the view, upon the types of modi cations to the base data that are considered during maintenance, and whether the technique works for all instances of databases and modi cations. Many incremental view maintenance algorithms have been developed [3, 5, 6, 10, 11]. These algorithms di er somewhat in the view de nitions they handle. For example, 4] considers select project join (SPJ) views only, while algorithms in [2] handle views de ned by any SQL or Datalog expression. Some algorithms depend on key information to deal with duplicate tuples [8] while ....

O. Shmueli, A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD International Conference on Management of Data, pages 240-255, Boston, Massachusetts, May 1984.

....database management systems. 1 INTRODUCTION The idea of using materialized views for the benefit of improved query processing has been proposed in the literature more than a decade ago. In this context, problems such as definition of views, composition of views, maintenance of views [BC79, KP81, SI84, BLT86, CW91, Rou91, GMS93] have been researched but one topic has been conspicuous by its absence. This concerns the problem of the judicious use of materialized views in answering a query. It may seem that materialized views should be used to evaluate a query whenever they are applicable. In ....

O. Shmueli and A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD Conference on the Management of Data, pages 240--255, Boston, MA, May 1984.

....see Hanson (1987) Segev and Park (1989) Segev and Fang (1990) Segev and Fang (1991) The basic idea is to reuse the maximal portion of the original sample when constructing the updated sample. Our results are thus a synthesis of classical techniques for updating materialized views Shmueli and Itai (1984), Shmueli and Itai (1987) Blakeley, Larson and Tompa (1986) Tompa and Blakely (1988) Hanson (1987) and Ceri and Widom (1991) with classical sampling algorithms. Devroye (1991) discusses a similar idea of sample reuse (coupled samples) in a simulation setting. Sample reuse is the basis of panel ....

Shmueli, O. and Itai, A. (1984). Maintenance of views, ACM SIGMOD International Conference on the Management of Data, pp. 244--255.

....the second case occurs if an update to a base table occurs which possibly affects a materialized view. The resulting problem preserving the consistency of the view is called view maintenance and has been discussed for, e.g. for (extended) relation 2 [8, 23, 38] and deductive databases [30, 24, 21, 44, 37]. The same problem occurs also for the materialization of functions within object bases [28] if the values of some object s attributes change, the materialized function value becomes invalid. However, since we do not necessarily materialize the view upon the underlying sources of our mediated ....

Oded Shmueli and Alon Itai. Maintenance of Views. In Sigmod Record, 14(2):240-255, 1984.

....have been developed. Most of them are designed for a traditional, centralized database environment, where it is assumed that view maintenance is performed by a system that has full control and knowledge of the view definition, the base relations, the updated tuples, and the view [HD92, QW91, SI84] These algorithms differ somewhat in the view definitions they handle. For example, BLT86] considers select projectjoin (SPJ) views only, while algorithms in [GMS93] handle views defined by any SQL or Datalog expression. Some algorithms depend on key information to deal with duplicate tuples ....

O. Shmueli and A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD International Conference on Management of Data, pages 240--255, Boston, Massachusetts, May 1984.

....case with many unconventional sources. For example, it is very difficult to generate a cost model for the face recognition or the video retrieval or terrain reasoning path planning sources of HERMES. Work on caching in databases has been done extensively through the notion of a materialized view [1, 2, 8, 9, 12, 13, 22, 23, 25, 26]. These papers show how views (and their materializations) may be defined for different kinds of databases such as relational DBMSs, object oriented DBMSs, and object relational systems. However, it is only recently that materialized views were studied in the context of mediated systems [19] ....

Oded Shmueli and Alon Itai. (1984) Maintenance of Views. In Sigmod Record, 14(2):240-255, 1984.

....from 245 GBytes to 167 MBytes. 1. 2 Related Work Many incremental view maintenance algorithms have been developed, but most of them have been developed for traditional, centralized database environments where the view maintenance system is assumed to have full control and access to the database [SI84, BLT86, CW91, HD92, GMS93, GL95, Qua96]. Segev et al. SP89a, SP89b, SF90, SF91] study materialized views in distributed systems. However, they only consider views over a single base table. As anomalies can arise due to processing delays of queries, keeping views in the data warehouse consistent with the source data requires the use ....

0. Schmueli and A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD International Conference on Management of Data, pages 240--255. Boston, Massachussetts, USA, May 1984.

....consistency without traditional distributed concurrency control. Furthermore, they offer a variety of consistency levels that are useful in the context of warehousing. Many incremental view maintenance algorithms have been developed for centralized database systems [BLT86, GMS93, CW91, HD92, QW91, SI84, CGL ] and a good overview of materialized views and their maintenance can be found in [GM95] Most of these solutions assume that a single system controls all of the base relations and understands the views and hence can intelligently monitor activities and compute all of the information ....

O. Shmueli and A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD International Conference on Management of Data, pages 240--255, Boston, Massachusetts, May 1984.

....query optimization algorithm. 1 Introduction The idea of using materialized views for the benefit of improved query processing has been proposed in the literature more than a decade ago. In this context, problems such as definition of views, composition of views, maintenance of views [BC79, KP81, SI84, BLT86, CW91, Rou91, GMS93] have been researched but one topic has been conspicuous by its absence. This concerns the problem of the judicious use of materialized views in answering a query. It may seem that materialized views should be used to evaluate a query whenever they are applicable. In ....

O. Shmueli and A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD Conference on the Management of Data, pages 240--255, Boston, MA, May 1984.

....have been developed. Most of them are designed for a traditional, centralized database environment, where it is assumed that view maintenance is performed by a system that has full control and knowledge of the view definition, the base relations, the updated tuples, and the view [HD92, QW91, SI84] These algorithms differ somewhat in the view definitions they handle. For example, BLT86] considers select project join (SPJ) views only, while algorithms in [GMS93] handle views defined by any SQL or Datalog expression. Some algorithms depend on key information to deal with duplicate tuples ....

O. Shmueli and A. Itai. Maintenance of views. In Proceedings of the ACM SIGMOD International Conference on Management of Data, pages 240--255, Boston, Massachusetts, May 1984.

....to recompute a view (to an empty relation) than to compute the changes to the view. Algorithms that compute changes to a view in response to changes to the edb are called incremental view maintenance algorithms. Several such algorithms with different applicability domains have been proposed [BC79, SI84, BLT86, BlTo88, BCL89, QW91, WDSY91, CW91, DT92]. View maintenance also has applications in integrity constraint maintenance and index maintenance. We present a new algorithm for incremental maintenance of a large class of views, including nonrecursive and recursive views (in SQL or Datalog extensions) defined using negation, grouping with ....

Oded Shmueli and Alon Itai. Maintenance of Views. In Proceedings of Annual Meeting, Sigmod Record, Vol 14, No. 2, 1984, 240-255.

....can be used to define several such summary tables with one statement. As changes are made to the data sources, the warehouse views must be updated to reflect the changed state of the data sources. The views either can be recomputed from scratch, or incremental maintenance techniques [BC79, SI84, RK86, BLT86, Han87, SP89, QW91, Qua96, CW91, GMS93, GL95, LMSS95, ZGHW95] can be used to calculate the changes to the views due to the source changes. Using the incremental maintenance approach, the warehouse can be updated either immediately as soon as a change from a source is received, or ....

O. Shmueli and A. Itai. Maintenance of Views. In Proceedings of ACM SIGMOD 1984 International Conference on Management of Data, pages 240--255, 1984.

....occur in one or more of the base relations upon which this view is defined. In such cases, the materialized view must be updated to incorporate the changes that occur in the base relation this is the problem of View Maintenance. View Maintenance is a subject that has been studied by many [1, 3, 5, 6, 8, 9, 10, 11, 15, 16, 17, 18, 21, 22, 25, 26, 27, 28, 29, 30, 31, 32, 33, 35, 23]. Every view maintenance technique in existence depends fundamentally upon the following key parameters: Computer Science Dept. Bucknell University, Lewisburg, PA 17837, USA. jameslu bucknell.edu. Supported by the NSF under Grant CCR9225037. y Institut fur Informatik, Universitat Freiburg. ....

.... without having to resort to a complex sequence of relational algebra and or deductive operations) The resulting problem preserving the consistency of the view is called view maintenance and has been discussed for, e.g. for (extended) relation [5, 17, 31] and deductive databases [22, 18, 15, 35, 30]. Though the above cited references comprehensively address the view maintenance problem in the setting of relational databases and in the case of object oriented databases [9, 21] there has been very little work when view definitions can contain well founded modes of negation in them in ....

Oded Shmueli and Alon Itai. Maintenance of Views. In Sigmod Record, 14(2):240-255, 1984.

....quickly evaluate to an empty relation) than to compute the changes to the view. Algorithms that compute changes to a view in response to changes to the base relations are called incremental view maintenance algorithms. Several such algorithms with different applicability domains have been proposed [BC79, NY83, SI84, BLT86, BT88, BCL89, CW91, Kuc91, QW91, WDSY91, CW92, DT92, HD92]. View maintenance has applications in integrity constraint maintenance, index maintenance in object oriented databases (define the index between attributes of interest as a view) persistent queries, active database [SPAM91, RS93] a rule may fire when a particular tuple is inserted into a view) ....

Oded Shmueli and Alon Itai. Maintenance of Views. In Sigmod Record, 14(2):240-255, 1984.

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O. Shmueli and A. Itai. Maintenance of views. In Proc of the 1984 ACM SIGMOD Intl. Conference on Management of Data, pages 240--255. ACM Press, 1984.

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