A transaction-based approach to relational database specification
TL;DR: Although it is shown that transaction- based specification and constraint-based specification are incomparable, constraints of practical interest that have corresponding transactional schemas are identified and the preservation of constraints by transactions is studied.
Abstract: An operational approach to database specification is proposed and investigated. Valid database states are described as the states resulting from the application of admissible transactions, specified by a transactional schema. The approach is similar in spirit to the modeling of behavior by methods and encapsulation in object-oriented systems. The transactions considered are line programs consisting of insertions, deletions, and modifications, using simple selection conditions. The results concern basic properties of transactional schemas, as well as the connection with traditional constraint schemas. In particular, the expressive power of transactional schemas is characterized. Although it is shown that transaction-based specification and constraint-based specification are incomparable, constraints of practical interest that have corresponding transactional schemas are identified. The preservation of constraints by transactions is also studied.
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Journal Article•
IBM1
TL;DR: This short paper motivates the approach, surveys research and its applications, and discusses how principles and techniques from database research can further develop the artifact-centric paradigm.
Abstract: Traditional approaches to business process modeling and wo rkflow are based on activity flows (with data often an afterthought) or documents (with processing o ften an afterthought). In contrast, an emerging approach uses(business) artifacts, that combine data and process in an holistic manner as the ba sic building block. These correspond to key business entities w hich evolve as they pass through the business’s operation. This short paper motivates the approach,surveys research and its applications, and discusses how principles and techniques from database mana gement research can further develop the artifact-centric paradigm.
401 citations
TL;DR: This paper addresses the problem of formalizing the evolution of a database under the effect of an arbitrary sequence of update transactions by appealing to a first-order representation language called the situation calculus, and develops a database version of the frame problem in artificial intelligence.
Abstract: We address the problem of formalizing the evolution of a database under the effect of an arbitrary sequence of update transactions. We do so by appealing to a first-order representation language called the situation calculus, which is a standard approach in artificial intelligence to the formalization of planning problems. We formalize database transactions in exactly the same way as actions in the artificial intelligence planning domain. This leads to a database version of the frame problem in artificial intelligence. We provide a solution to the frame problem for a special, but substantial, class of update transactions. Using the axioms corresponding to this solution, we provide procedures for determining whether a given sequence of update transactions is legal, and for query evaluation in an updated database. These procedures have the desirable property that they appeal to theorem-proving only with respect to the initial database state. We next address the problem of proving properties true in all states of the database. It turns out that mathematical induction is required for this task, and we formulate a number of suitable induction principles. Among those properties of database states that we wish to prove are the standard database notions of static and dynamic integrity constraints. In our setting, these emerge as inductive entailments of the database. Finally, we discuss various possible extensions of the approach of this paper, including transaction logs and historical queries, the complexity of query evaluation, actualized transactions, logic programming approaches to updates, database views, and state constraints.
99 citations
84 citations
TL;DR: A generalized relational model which is capable of representing and manipulating disjunctive and maybe kinds of information is presented and an operator to remove redundant information in M-tables is presented.
Abstract: A generalized relational model which is capable of representing and manipulating disjunctive and maybe kinds of information is presented. A data structure, called M-table, is defined, and the information contained in the M-table is precisely stated. Redundant information in M-tables is characterized, and an operator to remove this redundant information is presented. The relational algebra is suitably generalized to deal with M-tables. Additional operators, R-projection and merge, are presented. Queries can be expressed as a combination of the various generalized relational algebraic operators. The M-table accurately models the two bounds on the external interpretation of a query. The sure component of an M-table corresponds to one of the bounds which is the set of objects which belong to the external interpretation of the query. The maybe component of an M-table corresponds to the other bound which is the set of objects for which the possibility of belonging to the external interpretation of the query cannot be ruled out. >
67 citations
Proceedings Article•
03 Sep 1991TL;DR: In this paper, an initial study on characterizing migration inventories of transactions is presented, and three update languages are considered: SL, CSL, and CSL+ which allows hot,h positive and negative conditionals.
Abstract: In a class hierarchy, a “role set” is t,he set of classes where an object may reside simultaneously. A “migration pattern” is a sequence of role sets. A “migration inventory,” which is a set, of migrat,ion patterns, is viewed as a dynamic const,raintm on ohjrct migration. A set of transact ious is “sound” wrt a11 inventory if it. generates only pat.t.t~rns in the invrntory; “complete” if all pat,terns in the invent,ory can be generated. An initial stucly on characterizing migration inventories of transact,ions is presented. Three update languages are considered: SL which contains five operat,ors, CSL+ which ext rn(ls SL wit.h posit.ivc conditionals, and CSL which allows hot,h positive and negative condit.ionals. Four kinds of invent.orics are studied based on ln~znrss and znj~~,rtl~ntr s/art. It is shown that inventories produced by SL t,ransactions are regular and every regular inventory can be generated by SL transactions. Soundness and complet,eness for SL t,ransactions are decidahlt3. lnvc\llt,orics gpnrrated by CSL (CSL+) t,ra.nsactions arc r.e‘. and every r.e. inventory can be generat,rd by (:SL+ (CSL) transa.ctions under nonimmediate st,art,. It is also show t,hat, every r.e. immediate-start invent,ory can be obtained by a left quotient, of t,he invent,ory of CSL+ (CSL) transactions hy a regular seb. The exact, charact#erizat.ions are open. However, cvrry contrxl-frcr srt can be generat,ed. Soundness and rmllplPt~enms for ($1, (CSL+) t,ransa.ctions are undecidahlr.
56 citations
References
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01 Jan 1979
42,654 citations
Book•
01 Jan 1979
TL;DR: The second edition of a quarterly column as discussed by the authors provides a continuing update to the list of problems (NP-complete and harder) presented by M. R. Garey and myself in our book "Computers and Intractability: A Guide to the Theory of NP-Completeness,” W. H. Freeman & Co., San Francisco, 1979.
Abstract: This is the second edition of a quarterly column the purpose of which is to provide a continuing update to the list of problems (NP-complete and harder) presented by M. R. Garey and myself in our book ‘‘Computers and Intractability: A Guide to the Theory of NP-Completeness,’’ W. H. Freeman & Co., San Francisco, 1979 (hereinafter referred to as ‘‘[G&J]’’; previous columns will be referred to by their dates). A background equivalent to that provided by [G&J] is assumed. Readers having results they would like mentioned (NP-hardness, PSPACE-hardness, polynomial-time-solvability, etc.), or open problems they would like publicized, should send them to David S. Johnson, Room 2C355, Bell Laboratories, Murray Hill, NJ 07974, including details, or at least sketches, of any new proofs (full papers are preferred). In the case of unpublished results, please state explicitly that you would like the results mentioned in the column. Comments and corrections are also welcome. For more details on the nature of the column and the form of desired submissions, see the December 1981 issue of this journal.
40,020 citations
IBM1
TL;DR: In this article, a model based on n-ary relations, a normal form for data base relations, and the concept of a universal data sublanguage are introduced, and certain operations on relations are discussed and applied to the problems of redundancy and consistency in the user's model.
Abstract: Future users of large data banks must be protected from having to know how the data is organized in the machine (the internal representation). A prompting service which supplies such information is not a satisfactory solution. Activities of users at terminals and most application programs should remain unaffected when the internal representation of data is changed and even when some aspects of the external representation are changed. Changes in data representation will often be needed as a result of changes in query, update, and report traffic and natural growth in the types of stored information.Existing noninferential, formatted data systems provide users with tree-structured files or slightly more general network models of the data. In Section 1, inadequacies of these models are discussed. A model based on n-ary relations, a normal form for data base relations, and the concept of a universal data sublanguage are introduced. In Section 2, certain operations on relations (other than logical inference) are discussed and applied to the problems of redundancy and consistency in the user's model.
4,990 citations
Journal Article•
TL;DR: A model based on n-ary relations, a normal form for data base relations, and the concept of a universal data sublanguage are introduced and certain operations on relations are discussed and applied to the problems of redundancy and consistency in the user's model.
3,311 citations
01 Jan 1980
TL;DR: A large part of as mentioned in this paper is a description of relations, their algebra and calculus, and query languages that have been designed using these concepts, and explanations of how the theory can be used to design good systems.
Abstract: A large part is a description of relations, their algebra and calculus, and the query languages that have been designed using these concepts. There are explanations of how the theory can be used to design good systems. A description of the optimization of queries in relation-based query languages is provided, and a chapter is devoted to the recently developed protocols for guaranteeing consistency in databases that are operated on by many processes concurrently
1,934 citations