E. Teniente and A. Oliv, Updating the Knowledge Base while Maintaining their Consistency, The VLDB Journal, Vol.4, No. 2, 1995, pp. 193-241.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....provides a method to reduce all dynamic ICs to a form that can be evaluated in each state, taking into account only the facts of current and previous states. Implementations: A survey of the early methods in the area of IC maintenance is founded in [25] and that of the current methods are in[55] [77] provides a comparison of some techniques for view updating and IC maintenance. IC maintenance based on the generation and execution of active rules are provides in [13] 29] 48] 15] 47] aim at incorporating the information provided by IC into the update request then unfolding the resulting ....

....a comparison of some techniques for view updating and IC maintenance. IC maintenance based on the generation and execution of active rules are provides in [13] 29] 48] 15] 47] aim at incorporating the information provided by IC into the update request then unfolding the resulting expression. [77] takes into account the IC every time that a new update is considered. 46] 32] 53] develop dynamic IC enforcement. 41] describes a proposed model for incorporating declarative IC maintenance in an object oriented database management system. 36] provides protocols for IC checking in federated ....

E. Teniente and A. Oliv, Updating the Knowledge Base while Maintaining their Consistency, The VLDB Journal, Vol.4, No. 2, 1995, pp. 193-241.

....enforcement as an alternative to veri cation. Generally spoken, enforcement aims at systematically modifying a program speci cation such that the result is consistent with respect to the speci ed set of invariants. This has some tradition in the eld of logic programming and deductive databases [2, 3, 4, 8, 10, 15, 16] and also 1 appears as one of the goals of active databases [1, 6, 12, 13] Below we shall brie y compare our work with this related work. It does not make much sense to allow arbitrary changes to program speci cations in consistency enforcement. Therefore, the primary guideline underlying our ....

....the aspect of feedback any more. 1.3 Related Work As indicated above there is a large amount of comparable work in the eld of logic programming and deductive databases. The work in [9, 10] contains a detailed comparison of the work in this eld and extends an earlier comparative analysis in [15]. One conclusion to be drawn from this comparison is that the work in [10] presents the most sophisticated approach in this 3 area currently known. Thus, it will be enough to compare our work with the one of Mayol and Teniente [10] Nevertheless, let us brie y justify this reduction to just one ....

E. Teniente, A. Olive. Updating Knowledge Bases while Maintaining their Consistency. The VLDB Journal 4, 1995, 193-241.

....If an update of the first kind occurs to a view, whether materialized or not, the problem occurs on how to reflect the update correctly by changing the base tables appropriately. This problem is called the view update problem and has been discussed extensively for relational [6, 13, 15] deductive [6, 32, 42, 43], and object oriented [1, 14, 31, 35] databases. However, our objective is slightly different. As motivated by an example in Section 2.2, we do not necessarily assume that an update occurring to a view has to be reflected within some underlying source. Instead, we assume that the view itself ....

....its definition is affected by the update. This kind of update affecting the view s definition is typically not treated within the view update literature. One exception are deductive databases, where the addition or deletion of rules to the definition of an intensional predicate is discussed [42]. However, they neither materialize nor preprocess the view for efficiency reasons. Within the traditional context, 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 ....

E. Teniente. Updating knowledge bases while maintaining their consistency. VLDB Journal, 1994. to appear.

....considerable attention in the literature of the past decade. Most proposed techniques for integrity maintenance rely on monitoring by a generic application independent program that verifies that updates do not violate semantic constraints [Nic82] LST86] BDM88] JJ91] Cho92] Ple93a] Ten95] Ple95] Another popular approach is based on maintenance by transactions [Sto75] GM79] Lip90] CW90] LTW93] The former technique relieves the user from the burden of implementing database transactions in a way such that no constraint is violated. The latter requires that the ....

Teniente, Ernest and Oliv'e, Antoni. Updating Knowledge Bases While Maintaining Their Consistency. The VLDB Journal, 4(2):193--241, 1995. 25

.... that also starts with a given update and the constraints but now, if some constraint is violated, an attempt is made to find a repair, that is, an additional set of insertions and or deletions of facts to be added to the update, such that the resulting update satisfies all integrity constraints (Teniente and Oliv , 1995). Based on the time in which the method can be applied to enforce the constraints, there are two approaches. The first is a run time approach, that must be carried out in the time the update takes place. It takes into account the information provided by the update request and the contents of the ....

....are integrity maintenance methods. Time in which the method can be applied to enforce the constraints: if it is a run time or a compile time method. Some methods with run time approach are Kowalski et al. 1987) Moerkotte and Lockemann (1991) Palopoli and Torlone (1992) W thrich (1993) Teniente and Oliv (1995). Examples of compile time methods are Ceri and Widom (1990) Wallace (1991) Ceri et al. 1994b) Pastor and Oliv (1994) Widom et al. 1994) Other criteria to group constraint enforcement methods have been presented in the literature. For example, one of the criteria that Grefen and Apers ....

Teniente, E. and Olivé, A. (1995) Updating knowledge bases while maintaining their consistency. The VLDB Journal, 4(2), 193-241.

....has received considerable attention in the literature of the past two decades. Most proposed techniques for integrity maintenance rely on monitoring by a generic application independent program that verifies that updates do not violate semantic constraints [20] 15] 3] 10] 5] 22] [31], 24] Another popular approach is based on maintenance by transactions [30] 8] 14] 4] 11] The former technique relieves the user from the burden of implementing database transactions in a way such that no constraint is violated. The latter requires that the specification of updating ....

Teniente, E. and Oliv'e, A. Updating Knowledge Bases While Maintaining Their Consistency. The VLDB Journal, 4(2):193--241, 1995. This article was processed using the L A T E X macro package with LLNCS style

....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. ....

.... 5 Conclusions and Related Work Whenever an update occurs to a view, whether materialized or not, the problem of how to reflect the update correctly by changing the base tables appropriately is called the view update problem and has been discussed extensively for relational [3, 8, 10] deductive [3, 26, 32, 33], and object oriented [9, 25, 29] databases. In particular, the view itself or, to be more precise, its definition is affected by the update. This kind of update affecting the view s definition is typically not treated within the view update literature. One exception are deductive ....

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E. Teniente. Updating knowledge bases while maintaining their consistency. VLDB Journal, 1994. to appear.

....by the update. This kind of update affecting the view s definition is typically Mediated View Maintenance 3 not treated within the view update literature. One exception are deductive databases, where the addition or deletion of rules to the definition of an intensional predicate is discussed [29]. However, they neither materialize nor preprocess the view for efficiency reasons. Within the traditional context, 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 ....

E. Teniente and A. Olive. Updating knowledge bases while maintaining their consistency. Report de recerca, Universitat Politecnica de Catalunya, Report LSI-94-25-R. Barcelona, Spain. 1994.

....A deductive database is called consistent if it satisfies a set of integrity constraints. When applying a transaction, database consistency may be violated. That is, the transaction may falsify some integrity constraint. An approach to deal with this problem is that of integrity maintenance [ML91, Wt93, Ger94, CFPT94, TO95, Maa98, Sch98], which is concerned with trying to repair integrity constraints violations by performing additional updates that restore consistency of the database. The methods proposed so far for integrity maintenance have been mainly concerned with the generation of a complete set of repairs of integrity ....

....updates of underlying base facts. Moreover, updates of base facts obtained as a result of view updating could also violate other integrity constraints. For these reasons, it becomes necessary to integrate view updating into the process of integrity maintenance. Existing methods for view updating [KM90, Wt93, CST95, TO95, Dec96, LT97] have been mainly concerned with the effective generation of all possible translations that satisfy a view update request. However, they have paid little attention to efficiency issues. Thus, for instance, they do not care about exploring alternatives that do not lead to valid translations or ....

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Teniente, E.; Oliv, A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....example [8] If a violation is detected, the update is rolled back in its entirety. The main drawback of this approach is that the user may not know which additional changes are needed to satisfy all the integrity constraints. An alternative approach is that of integrity constraint maintenance [14, 20, 3, 17, 13, 1], which tries to repair integrity constraint violations by performing additional updates, other than the requested ones, to restore database consistency. Deductive databases contain also deductive rules that allow to deduce new (view or derived) facts from those (base) facts explicitly stored in ....

....the database. Dealing with Modification Requests : 193 Then, a request to update a derived fact must be translated into correct updates of the underlying base facts, since the view extension is completely defined by the application of the deductive rules. This problem is known as view updating [9, 10, 20, 5, 17, 7, 13]. View updating and integrity constraint maintenance are strongly related. On one side, an update obtained as a result of translating a view update request can violate an integrity constraint. On the other, repairing an integrity constraint defined through some derived predicate may require to ....

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Teniente, E.; Oliv'e, A. "Updating Knowledge Bases while Maintaining their Consistency ". The VLDB Journal . Vol. 4, Num. 2, 1995, pp. 193-241.

....constraint enforcement are strongly related. On one hand, a translation obtained by view updating could violate some integrity constraint. On the other, view updating must be performed when considering a repair of an integrity constraint through an update of a derived fact. Moreover, as shown in [TO95], view updating and integrity constraint checking can be successfully performed as two separate steps, while view updating and integrity constraint maintenance cannot. This paper reviews previous research in the field of view updating and integrity constraint maintenance. Its goal is to identify ....

....solving these problems and to summarize the achievements of previous methods according to those features. A survey of the early methods in the area of integrity constraint maintenance is provided in [FP93] A comparison of some techniques for view updating and integrity maintenance is given in [TO95]. This paper is structured as follows. Section 2 discusses on the relevant features to be taken into account during view updating and integrity constraint maintenance and it provides a general classification and comparison framework of relevant work according to these features. Section 3 ....

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Teniente, E.; Oliv, A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....LS93, Ull94] If this constructive procedure fails, then [IC compliant] QC holds. The Constructive Method for Query Containment Checking is based on the reduction of the QC problem to the view updating problem [FTU98] In particular, our method specializes the Events Method for view updating [TO95] to focus more on the characteristic aspects of QC checking. Our 3 approach is similar to that of [LMSS93, LS95] which translates QC to the problem of query satisfiability. However, the query satisfiability methods that [LMSS93, LS95] provide impose stronger restrictions on the cases that they ....

E. Teniente, A. Olivé: "Updating Knowledge Bases while Maintaining their Consistency". The VLDB Journal, Vol. 4, No. 2, 1995, pp. 193-241.

....modifications of base and derived facts that the user wants to perform. Moreover, the user can also specify a set of facts for which s he wants to prevent certain kinds of updates to be induced by a transaction (this functionality is usually known as prevention of side effects on others views [TO95]) Updates to be performed as well as updates to be prevented are specified in our method by means of a goal that contains positive and negative events, respectively. A special side effect prevention is obtained with the event iIc that allows our method to handle integrity constraints ....

....this aspect in this paper. If a predicate P has a recursive definition, the method could enter in a infinite loop and not terminate. To avoid this situation, we can adapt some of the existing loop checking techniques in the logic programming field [BAK91, Bol93] in a similar way as described in [TO95]. Our major concern when proposing this method has been to provide an efficient method for dealing with integrity constraints maintenance and view updating. However, effectiveness issues have also been considered as shows the fact that our method obtains all possible translations that satisfy an ....

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Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", to appear in the VLDB Journal, Vol. 4, Num. 2, 1995.

....i.e. updates of base facts, updates of derived facts, updates of deductive rules and updates of integrity constraints. Several problems may arise when updating a deductive database [Abi88] During last years much research has been devoted to different database updating problems like view updating [KM90, LS91, GL91, TO95, CHM95, Dec96], materialized view maintenance [CW91, HD92, UO92, GMS93, GM95] integrity constraints checking [BDM88, SK88, DW89, K c91, Oli91, GCM 94] integrity constraints maintenance [CW90, ML91, W t93, TO95, Dec96] or condition monitoring [RC 89, HCK 90, QW91] Up to now, the general approach of the ....

Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....constraints should be performed. This technique is based on the definition of a graph which explicitly states all relationships between integrity constraints and repairs. Our technique is directly applicable to the methods we have proposed in the past for updating consistent deductive databases [MT95, TO95] and it could be be easily adapted for improving efficiency of most of the existing integrity constraints maintenance methods. Second, we present an approach for integrating the treatment of integrity constraints to be checked and integrity constraints to be maintained. This approach is based on ....

....We will use these rules for obtaining the graph which contains the relationships between constraints and repairs. Our previous work in the field has been mainly devoted to the definition of a sound and complete method for updating deductive databases while maintaining their consistency [TO95] and on considering efficiency issues on the treatement of view updates [MT93, MT95] This paper extends our previous work by considering efficiency issues in the treatement of integrity constraints maintenance and also by proposing an approach for incorporating in a single method integrity ....

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Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....interrelationships with other updating problems. This was also the case of our group s previous work on the subject. However, a distinguishing feature of the methods we proposed for tasks such as integrity checking and maintenance, view updating and view materialization, and condition monitoring [Oli91, UO92, MT93, TO95, PO95] was the common theoretical basis upon which they all were developed. This basis has facilitated their merging into an integrative framework [Oli91, UO92] and their uniform specification and combination [TU95] in terms of this framework. Furthermore, by using these results, we have been able to ....

....updating base facts, FOLRE provides other advanced update capabilities the appropriate handling of which requires, sometimes, the database designer to specify additional knowledge about derived predicates and integrity constraints. These capabilities are: Updates of derived facts (view updates) [KM90, TO95, Dec96]: since only base facts are stored on the database, updates involving derived predicates are automatically translated by our system into updates of the underlying base facts. Integrity Constraints Enforcement: FOLRE allows two different integrity enforcement policies: integrity checking [SK88, ....

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Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....to reach such a state. Otherwise, it is not possible. 5.2.2 Preventing Side Effects Due to the deductive rules, non desired updates may be induced on some derived predicates when applying a transaction. We say that a side effect occurs when this happens. The problem of preventing side effects [TO95] is concerned with determining a set of base fact updates which, appended to a given transaction, ensure that the application of the resulting transaction to the current state of the database will not induce the undesired side effects. In general, several solutions may exist and the user must ....

....resulting transaction that does not induce the insertion of Unemp(Maria) is T = iLa(Maria) iWorks(Maria) 5.2.3 Repairing Inconsistent Databases Sometimes it may happen that a database reaches an inconsistent state. In this case, it raises the problem of repairing inconsistent databases [TO95]. Given an inconsistent database state, the problem is to obtain a set of updates of base facts that restore the database to a consistent state. In general, several solutions may exist and the database administrator should select one of them. In our framework, this problem can be specified as the ....

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Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", to appear in the VLDB Journal, 1995.

.... u even. The corresponding properties on K are that K is allowed and stratified (or callconsistent) In this section we will present the main theorems for soundness and completeness of the Events Method. The technical proofs are omitted from this paper due to lack of space and can be found in [TO94]. 6.1 Soundness The Events Method is sound in the sense that, given a knowledge base K and its associated augmented knowledge base A(K) if the method obtains a translation T for an update request u, then 30 the application of T to K (that is, inserting and or deleting the base facts ....

Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", Research Report LSI-94-25-R, UPC, Barcelona, 1994.

....strong interrelationships with other updating problems. This was also the case of our group s previous work on the subject, from which several competitive methods were produced for tasks such as integrity checking and maintenance, view updating and view materialization, and condition monitoring [Oli91, UO92, MT93, TO95, PO95]. However, a distinguishing feature of our methods is the common theoretical basis upon which they all were developed, which has facilitated their merging into a integrative framework [Oli91, UO92] for dealing with update problems in deductive databases as well as for their specification and ....

.... In FOLRE, we have implemented two methods which are able to compute each of these interpretations: The upward method [UO92] computes the upward interpretation and it is able to incrementally handle integrity checking, materialized view maintenance and condition monitoring; the downward method [MT93, TO95] computes the downward interpretation and handles view updating and integrity maintenance appropriately. We integrate the treatment of updates by using these two methods, which take into account a unique set of event rules. The generation of predefined transactions is also based on taking into ....

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Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....6 discuses related work. Finally, section 7 presents our conclusions and points out further work. 1 For more details, see section 6 below. 3 2. Base Concepts In this section, we briefly review some definitions related to Deductive Databases, Queries, Query Containment and View Updating [Llo87, Ull88, Sag88, Ull89, TO95]. 2 . 1 Deductive databases Throughout the paper, we consider a first order language with a universe of constants a, b, c, a 1 , b 1 , a set of variables x, y, z, x 1 , y 1 , a set of predicate names P, Q, V, P 1 , Q 1 , and no function symbols. A term is a variable or a ....

....predicates we provide already implies the negation of the containing query in the rule body. Therefore the view updating methods we choose, as stated in point 1 above, should at least be capable of performing view updates on derived predicates defined in such a way. The Events Method [TO95], for instance, is a view updating method that fits well in these requirements. All the examples we show in this paper are performed successfully by this method and, thus, the containment problems they pose are solved in a satisfactory way. Our independence of particular methods also allows us to ....

E. Teniente, A. Olivé: "Updating Knowledge Bases while Maintaining their Consistency". The VLDB Journal, Vol. 4, No. 2, 1995, 193-241.

....a graph, the Precedence Graph, which explicitly states all relationships between repairs and potential violations of integrity constraints. Information provided by this graph is directly applicable to the methods we have proposed in the past for handling consistent updates in deductive databases [MT93, MT95, TO92, TO95] and it could be easily adapted to be applicable to other existing methods. A different approach to enforce database consistency is integrity checking; which is concerned with developing methods for checking whether a given update violates an integrity constraint (see for example [Oli91, GCMD94] ....

Teniente, E.; Olivé, A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....of deductive databases, as known from, e.g. GMN84, Ull88] In section 2, we describe the general approach to using any given method for view updating also for database validation. For illustrating our approach, we describe its application to a known method for view updating, the Events Method [TO92, TO95], in section 3. We give reference and compare to related work ( Kun84, BM86, BDM88, IKH92, CDM93, LMSS93, GSUW94] along the way. We conclude with an outlook on the further use of view updating methods for knowledge assimilation tasks such as schema updating, transaction design and belief ....

....method must allow, at least, to express the declarative definitions of the tasks, given in section 2. Second, if there exists some solution that satisfies a given request, the method obtains one such solution (but not necessarily several or even all of them) We have considered the Events Method [TO92, TO95] which fulfils the two requirements stated above for the class of stratified databases since the declarative definition of the schema validation tasks may be defined in this class of databases and because it was proved in [TO95] that the Events Method is sound and complete for stratified and ....

[Article contains additional citation context not shown here]

E. Teniente, A. Olivé: Updating Knowledge Bases while Maintaining their Consistency, The VLDB Journal, Vol. 4, No. 2, 193-241, 1995.

....a graph, the Precedence Graph, which explicitly states all relationships between repairs and potential violations of integrity constraints. Information provided by this graph is directly applicable to the methods we have proposed in the past for handling consistent updates in deductive databases [MT95, TO95] and it could be easily adapted to other existing methods. A different approach to enforce database consistency is integrity checking; which is concerned with developing methods for checking whether a given update violates an integrity constraint [Oli91, GCMD94] In this case, when a violation is ....

Teniente, E.; Olivé, A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, Vol. 4, Num. 2, 1995, pp. 193-241.

....and a set of updates that violates some integrity constraint, determine a 12 set of additional base fact updates to be appended to the original update set such that the resulting set satisfies all integrity constraints. In our system, these two problems are handled as a whole as proposed in [TO92, MT93, TO95]. Given a user update request which consists of a set of base and view updates, the View Updating and Integrity Constraints Maintenance Module automatically translates the request into transactions consisting only of base fact updates. This translation is performed by taking into account the view ....

Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", to appear in the VLDB Journal, 1995.

....is guaranteed that the database state resulting of applying the update is consistent; that is, it satisfies the set of its integrity constraints. Moreover, if view updates are requested, they are appropriately translated into updates of the underlying base facts. We also show how the Events Method [TO95] can be formulated in terms of this abductive framework. 1 Introduction Among other components, deductive database management systems include an update processing system that provides the users with a uniform interface in which they can pose different kinds of update requests like updates of base ....

....KM90, GL91, W t93, LPS94, TO95] is concerned with determining how a request to update a view should be appropriately translated into correct updates of the underlying base facts. In our previous work, we proposed a method for dealing with consistency preserving updates in deductive databases [TO92, TO95]. This method, called the Events Method, handles requests for updating base facts as well as derived facts following the integrity constraints maintenance policy. Several additional features of the method like handling insertions and deletions of deductive rules and integrity constraints, allowing ....

[Article contains additional citation context not shown here]

Teniente, E.; Olivé. A. "Updating Knowledge Bases while Maintaining their Consistency", The VLDB Journal, 4(2), 1995.

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