P. Grefen and P. Apers, Integrity Control in Relational Database Systems - An Overview, Journal of Data and Knowledge Engineering, 10 (2), 187-223, 1993.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....these restrictions. At the same time, only integrity data is stored in the database. In the field of information systems and database, the term integrity normally refers to the correctness or validity of the stored data, as defined explicitly by means of integrity constraints or integrity rules [26]. There are several terms integrity, consistency, validity and correctness used differently by different authors. We prefer to the term integrity. Motro [52] makes the distinction between two components of integrity: validity and completeness. We can say that a database has integrity if all ....

....about integrity control from four levels: the concept of IC, the representation of IC, the implementation of IC and IC in the federated database system. Concepts: 52] gives the meaning of the integrity of the database, which refers to the correctness or validity of the data in the database. [26] provides a survey for integrity control in the relational database systems. 63] gives a survey of methods for definition and enforcement of dynamic IC. At the same time, some semantic integrity concepts are specified in [19] 18] 33] 64] 78] 79] Representations: A description and assessment ....

P. Grefen and P. Apers, Integrity Control in Relational Database Systems - An Overview, Journal of Data and Knowledge Engineering, 10 (2), 187-223, 1993.

....we propose in the following sections could be applied with other formalisms (Petri nets, for example) 3. 2 Monitoring Constraints in a Cooperative Environment The fundamental hypothesis on which are based all constraints monitoring algorithm is that transactions are serializable and atomic [13]. Everything appears just like if the transactions were executed one after the other. Thus algorithms do not have to consider any kind of interaction between them. Moreover, transactions can be rolled back and in the case of constraints violation, the transaction is aborted. These hypothesis ....

P.W. Grefen and P.M. Apers. Integrity Control in Relational Database Systems -- An Overview. Data and Knowledge Engineering, 10(2), pages 187--223, 1993.

....An important functionality in databases (DB) is to maintain consistency. This functionality is generally ensured by the definition of integrity constraints (IC) which are logical assertions which must be satisfied at the end of each transaction. Much work has been devoted to this problem (see [9] for a good survey) and most commercial DBMS provide efficient tools to maintain consistency. However, few studies have been carried out for the handling of integrity constraints in multidatabase systems. In such systems, it is necessary to minimize the transfer of data among the involved sites, ....

....Section 6 we conclude and present some perspectives. 2 Integrity Constraints Checking. A database is consistent if and only if all integrity constraints are satisfied. However, the checking of all constraints after each transaction has a prohibitive cost. Numerous works have studied this problem [9]. A popular approach consists of checking constraints at the end of the transaction, using compilation techniques to reduce the checking time at execution [4, 2] Our work is based on this approach and therefore can be adapted to all constraint handling mechanisms provided by a DBMS using the ....

P. W. P. J. Grefen and P. M. G. Apers. Integrity Control in Relational Database Systems --- An Overview. Data & Knowledge Engineering, 10:187--223, 1993.

....we propose in the following sections could be applied with other formalisms (Petri nets, for example) 3.2. Monitoring Constraints in a Cooperative Environment The fundamental hypothesis on which are based all constraints monitoring algorithm is that transactions are serializable and atomic [15]. Everything appears just like if the transactions were executed one after the other. Thus algorithms 9 do not have to consider any kind of interaction between them. Moreover, transactions can be rolled back and in the case of constraints violation, the transaction is aborted. These hypothesis ....

P.W. Grefen and P.M. Apers. Integrity Control in Relational Database Systems -- An Overview. Data and Knowledge Engineering, 10(2), pages 187--223, 1993.

....L compiled(mod) L tested(mod) c2 graph list new(mod) L compiled(mod) L tested(mod) At the end of an activity and during its termination stage, the monitoring algorithm is called in order to check the constraints of the activity and of its parent. We use a violation prevention approach [8] to maintain the constraints. This means that the constraints are enforced before the updates of an activity are actually applied to its parent database. With this technique, we do not need to apply recovery methods in case of violation. When a constraint violation occurs, the user is informed ....

P.W. Grefen and P.M. Apers. Integrity Control in Relational Database Systems -- An Overview. Data and Knowledge Engineering, 10(2), pages 187--223, 1993.

....integrity constraints. Constraints ensure the validity of data held in the database, according both to the system and the user, and also ensure that subsequent updates on data will not violate these restrictions. There are many important research topics associated with constraints in databases [10], like constraint semantics, specification and enforcement. Although, constraints are considered vital for database applications, there is a major preventive factor for using complex constraints in large databases, namely their enforcement performance cost [9] The work described here is ....

....sequential constraint checking, by simulation. Finally, section 6 concludes the paper with a summary of our work and a discussion of future work. 2. Constraint Checking in Object Oriented Databases The imperative need for integrity maintenance in database systems is a long recognized fact [10]. However, it is still an active research area, since many issues involving integrity constraint specification and enforcement need to be resolved. Object oriented databases gave a new rise in the interest for integrity constraints because of the new structural and semantics capabilities they ....

P.W.P.J. Grefen and P.M.G. Apers, Integrity control in relational database systems - An overview, Data & Knowledge Eng. 10 (1993), 187-223.

....but in real world, business database modelling would be greatly benefited from a tool that allows both a clear definition and an efficient enforcement of constraints with exceptions. 1 Introduction The imperative need for integrity maintenance in database systems is a long recognized fact [14]. Constraints ensure the validity of data held in the database, according both to the system and the user, and also ensure that subsequent updates on data will not violate these restrictions. Modern business database applications impose many complicated relations and restrictions among data, named ....

....scheme we proposed is aimed at the database designer and not the end user. Therefore, its manual nature is not a great drawback, since it will not be used by ignorant people. However, our tool would be greatly benefited from an automatic or semi automatic analysis of constraint consistency [14]. The analysis will decide whether a newly inserted constraint is consistent with the rest of constraints and possibly suggest ways that this can be avoided by declaring some constraints or classes as exceptions. Previous work on constraint consistency is based on a logical formulation of both the ....

P.W.P.J. Grefen and P.M.G. Apers, Integrity control in relational database systems - An overview, Data & Knowledge Engineering, 10(2), 1993, 187-223.

....evaluation. Integrity constraints have been studied from various aspects since the introduction of the relational data model in 1970. In the late Eighties and early Nineties there were some attempts to provide overview papers on the foundations of integrity constraints in relational databases [8, 18, 33]. These presentations were independent of any particular integrity constraint specification language, in particular neither the SQL standard existing at that time nor SQL dialects as provided by major database management systems were considered. This paper surveys the state of the art of semantic ....

....can be found in [6, 43, 72] We have not considered integrity constraints in object oriented database because of the minor role these systems play in the current market. As already mentioned, there are also some overview papers on semantic integrity constraints in relational databases, e.g. [8, 18, 33]. However, these presentations were independent of the SQL standard as well as of the SQL dialects of commercially database management systems available at that time. Therefore, we felt that a survey paper on semantic integrity constraints was needed which gives an overview of semantic integrity ....

P. W. P. J. Grefen and P. M. G. Apers. Integrity Control in Relational Database Systems --- An Overview. Data & Knowledge Engineering, 10:187--223, 1993.

....son satisfechas. Sin embargo,laverificaci on del conjunto completo de restricciones luego de cada actualizaci on a una BD representa un costo insostenible. Numerosos trabajos han estudiado este problema [5, 13, 11] y los diferentes enfoques para abordarlo son presentados de manera resumida en [10]. Las soluciones que consisten en verificar las restricciones despu es de la ejecuci on de una transacci on (m etodos de detecci on) generalmente uti lizan t ecnicas de compilaci on para reducir el proceso de verificaci on durante la ejecuci on [3, 2] Nuestro trabajo est a situado dentro de este ....

P.W.P. J. Grefen and P. M. G. Apers. IntegrityControl in Relational Database Systems --- An Overview. Data & Knowledge Engineering, 10:187--223, 1993.

....are assertions defined on the database, which must be satisfied at the end of each transaction. Much work has been devoted to this problem [Nic82,CW90,GW93,CFPT94,GW97] and many DBMS provide now this functionality [IBM89,Syb89,ES97] Good surveys describing the various approaches are given in [GA93,FMP97]. In the great majority of cases, consistency management systems are designed for simple and classical flat transaction models and very few solutions have been proposed for the management of integrity constraints in the context of nested transactions. Although it seems natural that the nested ....

....assertions that must always hold in the database. A database state is consistent if and only if all constraints are satisfied. Much work concerning the checking of integrity constraints has already been done [Nic82,CW90,GW93,CFPT94,GW97] Good surveys describing the various approaches are given in [GA93,FMP97]. Some approaches are adapted for on line transactions, such as active rules and triggers [WC96] where the user is in charge of determining the events raising the checking of a given constraint. Other solutions use compilation techniques to reduce the constraint checking process at execution time ....

P. W. P. J. Grefen and P. M. G. Apers. Integrity Control in Relational Database Systems --- An Overview. Data & Knowledge Engineering, 10:187-- 223, 1993.

....papers by the Ingres group: Stonebraker,Wong Held, 1976] and which is not been taken care of by most data and knowledge base systems: constraints on the data are globally specified in the form of triggers, while security is defined using a single access matrix. See e.g. the overview paper [Grefen Apers, 93] which deals with integrity constraints in database systems and the paper [Paton,Diaz Barja, 93] about constraints in the form of rules in Object Oriented (O O) systems. Our current work on integrity and security in databases can be considered as a continuation of work by our group in the not ....

P.W.P.J. Grefen, P.M.G. Apers, Integrity control in Relational Database Systems - A n Overview, Data and Knowledge Engineering, Vol. 10, nr. 2 (March 1993), pp. 187-2 23. 19

....with the requirement of high performance constraint checking. The work in the field of integrity checking mainly considered the simplification of integrity constraints [Nic82] Little attention has been paid to the execution of integrity constraints, even though this is known to raise problems [GA93]. Because we deal with constraints as queries, we have to integrate optimization and parallelization techniques. The problem of multiple query optimization (or global optimization) has been examined in the past. In [SG90] the complexity of the multiple query optimization problem is studied and ....

P.W.P.J. Grefen and P.M.G. Apers. Integrity control in relational database systems -- An overview. Data & Knowledge Engineering, 10(2):187--223, 1993.

....a non redundant set of constraints is important because both the maintenance algorithms discussed here and the methods in the integrity enforcement get more costly exponentially 2 Naci S. Ishakbeyoglu and Z. Meral Ozsoyoglu in the former case when the size of the constraint set gets bigger (Grefen and Apers 1993). We adopt an incremental approach to maintaining constraints. That is, we assume that the current constraint base is consistent and non redundant, and test whether a new constraint to be inserted is redundant or contradictory to the current constraint base. These tests are in general exponential ....

Grefen, P. W. P. J., Apers, P. M. G., Integrity Control in Relational Database Systems - An Overview, Data & Knowledge Engineering 10 (1993), pp.

....it can already be noted that each possibility of doing an unveiling depends on a particular configuration of constraints and access privileges. We study, here, unveilings related to special configurations made of the so called binary integrity constraints which are 2 attribute constraints [GREF93], DELA94] and of select update privileges. These configurations are easily identifiable and can therefore be of some interest to database administrators when many relations, constraints and users are concerned. The present work extends [DELA96b] Two requirements have guided it. On the first ....

Greffen, P., Apers, P., Integrity Control in Relational Database Systems - An Overview, Data &Knowledge Engineering, 10 (1993), p187-223, North Holland, 1993.

.... Diagnosis, Repairing Inconsistencies, Repair Strategies 1 INTRODUCTION Numerous papers have been written on specifying and maintaining integrity constraints in databases since the first large database conference (Eswaran and Chamberlin 1975, Hammer and McLeod 1975) for an overview see, e.g. (Grefen and Apers 1993, Widom 1994) The aim has always been to develop c flIFIP 1996. Published by Chapman Hall 2 An Extensible Framework for Repairing Constraint Violations methods that efficiently check integrity constraints for violations. Several proposals on integrity maintenance have been made for ....

....c flIFIP 1996. Published by Chapman Hall 2 An Extensible Framework for Repairing Constraint Violations methods that efficiently check integrity constraints for violations. Several proposals on integrity maintenance have been made for relational, deductive and object oriented databases (Grefen and Apers 1993, Widom 1994, Celma et al. 1994, Jeusfeld and Jarke 1991) Nearly all of these approaches are passive, i.e. in case of constraint violations a rollback of the complete transaction is performed. For several applications, however, such a drastic action is insufficient. This holds in particular for ....

P. W. Grefen, P. M. Apers (1993) Integrity Control in Relational Database Systems - An Overview. Data & Knowledge Engineering 10:2 (March 1993), 187--223.

.... Uberl ndia, Uberl ndia, MG, Brazil (E mail: mamelia pitanga.ufu.br) 1 INTRODUCTION In the field of information systems and databases, the term integrity normally refers to the correctness or validity of the stored data, as defined explicitly by means of integrity rules or integrity constraints (Grefen and Apers, 1993). Integrity is a very important property of information systems. The lack of integrity has usually negative consequences (Oliv , 1995) Motro (1989) makes the distinction between two components of integrity: validity and completeness. We can say that a database has integrity if all its data are ....

....in this case, lack of completeness may lead the system to deduce facts that are not valid. In general, neither the full correctness with respect to the part of the real world modeled by the database is guaranteed, nor the completeness of the facts stored in the database is ensured (Motro, 1989; Grefen and Apers, 1993). For most systems, full integrity can only be achieved with human supervision, because the system cannot determine if a fact is true or false and it cannot detect changes in the Universe of Discourse (UD) To ensure integrity, one should check systematically the facts with respect to the UD. ....

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Grefen, P. and Apers, P. (1993) Integrity control in relational database systems - an overview. Data & Knowledge Engineering, 10(2), 187-223.

....5) We conclude with a discussion of current and future work (Section 6) There are important aspects of ICs we do not cover in this chapter. In particular, we do not discuss integrity constraint checking; that is, how best to check the consistency of the database with respect to ICs. We recommend [53] as a survey of this work. 2 Background This section contains a summary of the background and notation used in this chapter. Additional details concerning logic are found in [21] We use the language and terminology of logic databases ( 24] 67] and [68] as presented in [21] Logic databases ....

P. W. P. J. Grefen and P. M. G. Apers. Integrity control in relational database systems: An overview. Data and Knowledge Engineering, 10:187--223, 1993.

....database states or transitions between states which must be accepted or refused by the DBMS, via validation or rollback, to maintain consistency. A large amount of work has been published for years on integrity constraints for monoversion databases, which are databases without user versions. [GA93] gives a survey of the various approaches used to manage integrity constraints. Many papers are devoted to version models in different areas like temporal databases [Sarda90, TCG 93] CASE and CAD [Atw86, Reich89, Kat90, EC94] general purpose DBMS [Zdo86, AJ89, KBG89, TOC93, O2T95] However, as ....

P. Grefen and P. Apers. Integrity control in relational database systems - an overview. Data & Knowledge Engineering, 10(2):187--223, 1993.

....with a discussion of current and future work (Section 7) We note that there are important aspects of ICs we do not cover in this chapter. In particular, we do not discuss integrity constraint checking; that is, how best to check the consistency of the database with respect to ICs. We recommend [Grefen and Apers, 1993] as a survey of this work. 2 Background This section contains a summary of the background and notations used in this chapter. We use the language and terminology of logic databases ( Das, 1992] Lloyd, 1987] and [Lobo et al. 1992] Logic databases express data, rules (views) and queries in ....

Grefen, P. W. P. J. and Apers, P. M. G. (1993). Integrity control in relational database systems: An overview. Data and Knowledge Engineering, 10:187--223.

....a transaction t is negative, we do not have to include b in t s view closure. Thus, some data in the view set are only conditionally read based on the values of items already read. Finally, many techniques proposed in the context of optimizing the processes of constraint evaluation and validation [8] can be applied directly to optimize the size of closures. Constraint subsumption [10] is such a case. Let fC 1 ; C 2 : Cn g be a set of constraints. An additional constraint C is subsumed by C 1 ; C 2 : Cn if, whenever C is violated then so is at least one C i 2 fC 1 ; C 2 : Cn ....

....of imposing closure conditions. The size of closure sets can be reduced if a more elaborate definition of closure 398 Evaggelia Pitoura et al. is provided as suggested in Section 3, and the time for testing consistency can be minimized if advanced methods for testing consistency are employed [8]. Comparing these overheads to proposed methods of enforcing global serializability [7, 12, 21] our method still avoids creating direct conflicts between global transactions as global serializability methods do by enforcing them to update the same data items. Thus, although readsets may be large, ....

P. Grefen and P. Appers. Integrity control in relational database systems - an overview. Data and Knowledge Engineering, 10:187--223 (1993).

....classical way to manage consistency is to define integrity constraints, which are assertions that must be verified at the end of each transaction. Integrity constraints can concern single entities as well as several entities. A database is consistent if and only if all constraints are satisfied. [GA93] gives a survey of the various approaches used to manage integrity constraints. Versioning is also a major need in a growing number of applications. For instance, in design applications (e.g. CAD, CASE, etc. designers need to create and handle versions in order to cope with the trial and error ....

P. Grefen and P. Apers. Integrity control in relational database systems - an overview. Data & Knowledge Engineering, 10(2):187--223, 1993.

....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 the database, associated with data [TCG 93] As shown below, the introduction of temporal information generates consistency problems in presence of ....

P. Grefen and P. Apers. Integrity control in relational database systems - an overview. In : Data & Knowledge Engineering, 10(2):187--223, 1993.

....expressions of the formal language. Typically, extensions for first order logic are used for expressing integrity constraints, see e.g. Lip89] that explicitly must consider the change of data in time. Whereas for traditional databases a lot of work has been done on integrity constraints (see [GA93] for an overview) less attention has been paid on integrity constraints in the object oriented case. Object oriented databases provide means for storing complex data with behavioural abstractions through methods. Generally there is the feeling that integrity can be completely handled by the ....

....be always valid or temporary valid. These definitions will be used in the sequel. 2.3 Related Work There is a wide variety of languages proposed for semantic integrity constraints. Trigger languages are among the most investigated formalisms for expressing semantic integrity in conventional ( GA93] and even semantic ( Est89] data models. Others have taken different approaches to integrate object oriented data models and integrity constraints. Their work can be divided along the following guidelines: ffl Integrating an all purpose rule language. The active database paradigm ( BM91] uses ....

P. W. P. J. Grefen93 and P. M. G. Apers. Integrity control in relational database systems--An overview. Data & Knowledge Engineering, 10:187--223, 1993.

....transactions form the cornerstone of integrity constraint checking: Before a transaction commits, it ensures that all constraints are valid. If a constraint is violated, then the transaction may be aborted, the constraint may be corrected automatically, or an error condition may be raised [8]. This work was supported at Stanford by ARPA Contract F33615 93 1 1339, by the Anderson Faculty Scholar Fund, and by equipment grants from Digital Equipment Corporation and IBM Corporation. Unfortunately, the lack of inter site transaction mechanisms in federated databases renders ....

....global constraints that may be invalidated by operations on its corresponding database. Consequently, each global constraint is replicated at every site containing data involved in the constraint. We assume that any local constraints are managed within the appropriate database system (see, e.g. [8]) The constraint manager is notified of all changes ( Delta s) to the local database that may violate a constraint. For convenience, we may assume that delta notifications are sent at the end of each local update transaction; however, any granularity of delta notification can be handled by our ....

[Article contains additional citation context not shown here]

P.W.P.J. Grefen and P.M.G. Apers. Integrity control in relational database systems -- an overview. Journal of Data & Knowledge Engineering, 10(2), 1993.

....form the cornerstone of integrity constraint checking: Before a transaction commits, it ensures that all integrity constraints are valid. If a constraint is violated, then the transaction may be aborted, the constraint may be corrected automatically, or an error condition may be raised [GA93]. Unfortunately, the lack of inter site transaction mechanisms in federated databases renders traditional constraint checking mechanisms inapplicable. This paper addresses the problem of integrity constraint checking in federated databases; we make a threefold contribution. First, the constraint ....

....invalidated by operations on its corresponding database. Consequently, each global constraint is replicated at every site containing data involved in the constraint. We assume that any local constraints are managed within the appropriate database system using traditional mechanisms (see, e.g. [GA93]) The constraint manager is notified of all changes ( Delta s) to the local database that may violate a constraint. For convenience, we may assume that delta notifications are sent at the end of each local update transaction; however, as mentioned earlier, any granularity of delta notification ....

[Article contains additional citation context not shown here]

P.W.P.J. Grefen and P.M.G. Apers. Integrity control in relational database systems -- an overview. Journal of Data & Knowledge Engineering, 10(2), 1993.

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