Date, C. Referential integrity. In G. Gardaun, M. Edelberg, C. Zaniolo, H. Biller, and C. Delobel (eds.), Proceedings of the Seventh International Conference on Very Large Data Bases. Cannes, France: VLDB, 1981, pp. 2--12.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....Some considerations are marked with numbered gray arrows in Figure 24. The numbers in the following paragraphs refer to these numbers. 1. Codd [17] proposed that referential integrity should be an inherent rather than an implicit part of the relational model. This is not considered a good idea in [22] because it does not allow for specification of what should be done in case of a violation. Implicit, Declarative Explicit Declarative Inherent, Declarative Procedural create trigger create procedure not null check primary key on delete restrict unique create assertion references ....

C. J. Date. Referential integrity. In Proc. 7th International Conference on Very Large Data Bases, September 1981.

....from a practical and theoretical point of view: Referential integrity constraints (ric s) are a central concept of the relational database model and frequently used in real world applications. Referential actions (rac s) are specialized triggers used to automatically maintain referential integrity [Dat81]. While the local behavior of rac s is quite intuitive and easy to understand, Supported by grant no. GRK 184 1 97 of the Deutsche Forschungsgemeinschaft. c flACM PODS 97, Tucson, Arizona it is far from clear what their global semantics should be. In particular, different execution orders of ....

C. J. Date. Referential Integrity. In Proc. Intl. Conference on Very Large Data Bases, pages 2--12, Cannes, France, March 1981. IEEE Computer Society Press.

....SQL DDLs it is also possible to specify referential integrity constraints, which create foreign keys. This information is especially useful for the mapping process as it indicates ontological relations. The reader may note that referential integrity constraints enforce that inclusion dependencies [Dat81] are valid at all times. Therefore our relational model also contains: A set of inclusion dependencies I where each element has the form ( rl, 41) r2, 42) with rl, r 2 E R, 41 = all , a12 , a13 . and 42 = a21, a22, a23 . A c att( r 1 ) and 42 c att( r 2 ) 1 4 I = 1 421 and ....

Date C. J. Referential integrity. In Proceedings. of Intl. Conf. on Very Large Data Bases, pages 2 - 12, 1981

....entries a 1 . a m for attributes B . Brn appears in relation S. Inclusion dependencies make it possible to selectively define what data must be duplicated in what relations and thus they provide a valuable tool for database design [24, 59, 69] The central notion of refi renlial mtegriO [24, 29] can be expressed using IND s. Together with FITs, INl) s form the basis of the structural model of [67] l)cscriptions of logical databases written in a variety of languages can be translated into a common language which uses relations, Fl) s and IND s [45] Inclusion dependencies have also been ....

Date, C. Referential Integrity. Proceedings of the 7 th VIDB Conference, 1981, pp. 2-12.

....from a practical and theoretical point of view: Referential integrity constraints (ric s) are a central concept of the relational database model and frequently used in real world applications. Referential actions (rac s) are specialized triggers used to automatically maintain referential integrity [Dat81]. While the local behavior of rac s is quite intuitive and easy to understand, it is far from clear what their global semantics should be. In particular, different execution orders of rac s may lead to different outcomes, i.e. to ambiguities in determining the above Delta and D 0 . Supported ....

C. J. Date. Referential Integrity. In Proc. Intl. Conference on Very Large Data Bases, pages 2--12, Cannes, France, March 1981. IEEE Computer Society Press.

....problem for tree like INDs, which is a proper subclass of the subclass of noncircular INDs, is polynomial time decidable. Although the subclass of tree like INDs is somewhat restricted it covers many practical situations when inclusion dependencies are used to enforce referential integrity [Dat86]. The layout of the rest of this note is as follows. In Section 2 we briefly define the underlying concepts from relational database theory. In Section 3 we introduce the subclass of tree like INDs and reduced set of FDs and INDs. In Section 4 we present our main result which states that a set of ....

C.J. Date. Referential integrity. In Relational Database: Selected Writings, pages 41--63. Addison-Wesley, Reading, Ma., 1986.

....is satisfied in a database, if whenever the foreign key values of a tuple in the referencing relation do not contain null values, then these values are the primary values of some tuple in the referenced relation. Referential integrity enforces the satisfaction of such foreign key constraints [Dat86, HR96]. We continue to quote from Codd s definition of entity integrity [Cod90] No component of a foreign key is allowed to have an I marked value , where an I marked value in our terminology is a null value of the type value does not exist . Thus foreign key values also restrict the occurrence of ....

....[X A i ] 0, 0 and t i [R X] dne, dne . It can now be verified that r = # X#P(R) r X is the desired relation. # 7 Foreign key families and generalised referential integrity In the context of incomplete relations the fundamental constraint of referential integrity [Cod79, Dat86, HR96] also needs to be re evaluated. Herein we define the notion of foreign key family being satisfied in a database. We show that the notion of a foreign key family in a database is faithful to the standard notion of foreign key in a database, and, in the absence of dne in relations, is a precise ....

C.J. Date. Referential integrity. In Relational Database: Selected Writings, pages 41--63. Addison-Wesley, Reading, Ma., 1986. 13

....can be done in time polynomial in the size of Sigma. 1 Introduction Functional dependencies (FDs) ULLM88, ATZE93] generalise the notions of entity integrity and keys [CODD79] and inclusion dependencies (INDs) MITC83, CASA84] generalise the notions of referential integrity and foreign keys [CODD79, DATE86]. In this sense FDs and INDs are the most fundamental data dependencies that arise in practice. Codd [CODD79] suggested the addition to the database domains of an unmarked null value, whose meaning is value at present unknown , which we denote by unk, in order to extend relations so that they ....

C.J. Date, Referential integrity. In: Relational Database: Selected Writings. Reading, Ma., Addison-Wesley, pp. 41-63, 1986.

....references left to an object anywhere in the system when it is deleted. This question of maintaining referential integrity at object deletion time is our primary concern in this section. Suppose that an object to be deleted still has a reference to it. There are three standard maintenance options [9]. The reference can be deleted as part of the transaction deleting the object (by placing a NULL in the reference pointer) the referencing object can be deleted, or the deletion of the object can be disallowed. Which of the three we want for each reference is specified once as part of the class ....

C. J. Date, "Referential Integrity," Proc. 7th Int'l Conf. Very Large Data Bases, 1981.

....record is discarded if the input value of registration id attribute already exists or is NULL. define rule studentunique is on append to student where student.registrationid = new.registrationid or new.registrationid ISNULL do instead nothing Now, let us consider the referential integrity [Date 1981]. Here, we have to guarantee that the values occurring for the attribute course name of student are a subset of the values that occur in the attribute name of the course class. We also need to assure 19 that the values occurring for the attribute tutor name of student are a subset of the values ....

Date 1981, Date, C. Referential integrity. In Proceedings of the Seventh International VLDB Conference Cannes, France, Sept. 1981.

....are presented, which give further insight into the problem of ambiguity of triggers. 1 Introduction The concept of referential integrity has been present in the relational model from the beginning [Cod70] Basically defined to guarantee the existence of referenced objects, it was refined by Date [Dat81] to a more active concept, ie the possibility to descriptively define reactions in order to compensate violations of referential integrity by so called referential actions. Thus, referential actions are used to automatically enforce integrity. This task is more involved than integrity checking : ....

C. J. Date. Referential Integrity. In Proc. Intl. Conference on Very Large Data Bases, pages 2--12, Cannes, France, March 1981. IEEE Computer Society Press.

....are more precise than the one (meaning zero or one) and many (meaning zero, one, or more) that are common in existing OODB systems. The notation focuses on an important subset of the constraints and triggers specifiable in a more generalized, rule based, integrity constraint mechanism, e.g. [7, 25], allowing this subset to be more easily specified and more efficiently implemented. The ultimate benefit of the notation will be to significantly ease OODB development and enhance data integrity. For example, the notation when supported by an OODB system makes possible a simple, high level ....

.... as previously mentioned, a number of OODB systems support composite objects, i.e. the is a part of relationship [16, 18, 19, 23] The notation proposed here for describing relationship semantics can be compared to other proposed schemes for defining similar semantics in the relational model [7, 17] and in proposed object oriented data models that include relations [1, 22] First, unlike these schemes, the proposed notation assumes a basic object oriented data model where most relationships are represented conceptually as object attributes that may reference other objects. The notation ....

[Article contains additional citation context not shown here]

C.J. Date, "Referential Integrity," Proc. 7th Int'l VLDB Conf., IEEE Computer Society Press, 1981, 2-12.

....is satisfied in a database, if whenever the foreign key values of a tuple in the referencing relation do not contain null values, then these values are the primary values of some tuple in the referenced relation. Referential integrity enforces the satisfaction of such foreign key constraints [Dat86, HR96]. We continue to quote from Codd s definition of entity integrity [Cod90] No component of a foreign key is allowed to have an I marked value , where an I marked value in our terminology is a null value of the type value does not exist . Thus foreign key values also restrict the occurrence of ....

....i g] 0; 0 and t i [R GammaX] dne; dne . It can now be verified that r = S X2P(R) r X is the desired relation. 2 7 Foreign key families and generalised referential integrity In the context of incomplete relations the fundamental constraint of referential integrity [Cod79, Dat86, HR96] also needs to be re evaluated. Herein we define the notion of foreign key family being satisfied in a database. We show that the notion of a foreign key family in a database is faithful to the standard notion of foreign key in a database, and, in the absence of dne in relations, is a precise ....

C.J. Date. Referential integrity. In Relational Database: Selected Writings, pages 41--63. Addison-Wesley, Reading, Ma., 1986.

....composed of a small set of very basic concepts which represent semantically irreducible units of information. This simplifies the process of schema design, and allows a simple, graphical representation of schemas. ffl The FDM is an entity based model, and therefore supports referential integrity [27] implicitly. It is also capable of supporting other important data model features such as object identity [66] and inheritance hierarchies of entity classes [102] ffl FDM schemas are easily extendible, i.e. entity classes and functions may be added or deleted without requiring reorganisation of ....

C.J. Date. Referential Integrity. In C. Zaniolo and C. Delobel, editors, VLDB 81 Conference, pages 2--12, Cannes, 1981. IEEE Computer Society Press.

....x of O i as one of its values for some instance y of O j , then deleting x from O i entails removing x from the set list of multiple A values for y, or nullifying the unique A value for y. y These rules are the object oriented analogs of the relational referential integrity rules (e.g. see [11]) An Overview of OPM and OPM Data Management Tools 7 Connection connection id [INT] distance [INT] Fragment owner 6 fragment id [INT] sequence [VARCHAR] length [INT] Contig Map owner contig id [INT] Person owns oe oe name [CHAR] person id [INT] j ....

C.J. Date. Referential integrity. In Relational Database - Selected Writings. Addison-Wesley (1986).

....problem for tree like INDs, which is a proper subclass of the subclass of noncircular INDs, is polynomial time decidable. Although the subclass of tree like INDs is somewhat restricted it covers many practical situations when inclusion dependencies are used to enforce referential integrity [Dat86]. The layout of the rest of this note is as follows. In Section 2 we briefly define the underlying concepts from relational database theory. In Section 3 we introduce the subclass of tree like INDs and reduced set of FDs and INDs. In Section 4 we present our main result which states that a set ....

C.J. Date. Referential integrity. In Relational Database: Selected Writings, pages 41--63. Addison-Wesley, Reading, Ma., 1986.

.... functional dependency, inclusion dependency 1 Introduction Functional dependencies (FDs) Arm74, Mai83, Ull88, AA93] generalise the notions of entity integrity and keys [Cod79] and inclusion dependencies (INDs) Mit83, CFP84] generalise the notions of referential integrity and foreign keys [Cod79, Dat86]. In this sense FDs and INDs are the most fundamental data dependencies that arise in practice. Relational database design in the presence of FDs is an established area in database theory, which has been researched for over twenty years [Cod74, BB79, Mai83, Ull88, AA93] The semantic justification ....

C.J. Date. Referential integrity. In Relational Database: Selected Writings, pages 41--63. Addison-Wesley, Reading, MA, 1986.

.... to non null values; iii) domain constraints for restricting the range of values of an attribute; and (iv) referential integrity constraints for expressing existence dependencies between tuples by associating a foreign key in a referencing relation with the primary keys of referenced relations [12]. Several relations, together with a number of relational constraints, are usually needed for representing a single class of objects: a class with only simple, single valued attributes can be represented using a single relation; however, representing an object class with set or list valued ....

C. J. Date. Referential integrity. In Relational DatabaseSelected Writings. Addison-Wesley, 1986.

....design we need not assume that NINDs are noncircular. 1 Introduction Functional dependencies (FDs) ULLM88, ATZE93] generalize the notions of entity integrity and keys [CODD79] and inclusion dependencies (INDs) MITC83, CASA84] generalize the notions of referential integrity and foreign keys [CODD79, DATE86]. In this sense FDs and INDs are the most fundamental data dependencies that arise in practice. Codd [CODD79] suggested the addition to the database domains of an unmarked null value, whose meaning is value at present unknown , which we denote by unk, in order to extend relations so that they can ....

....to incorporate NINDs into database design we define the notion of key based NINDs [MANN86, MANN88] which generalize the notion of foreign key as follows. A NIND R[X] S[Y] is said to be key based if Y is a key for S. In this case we consider X to be a foreign key of R with respect to S (cf. [DATE86]) We show that if a database schema is in BCNF with respect to a set of NFDs, F, and all the NINDs in a set of NINDs, I, are key based, then we have the desirable property that any NFD that is logically implied by F [ I is logically implied by F on its own and any NIND that is logically implied ....

[Article contains additional citation context not shown here]

C.J. Date, Referential integrity. In: Relational Database: Selected Writings. Addison-Wesley, Reading, Ma., pp. 41-63, 1986.

....the chain of nodes from the root (O) of the O tree to a node labeled s 0 , i.e. O:O 1 : Delta Delta Delta :O n :s 0 . For example, Ochain(Programmer, title) returns Programmer.Project.titleand Ochain(Programmer, Project) returns Programmer.Project. 4. 2 Data Model Integrity constraints [28, 29, 30] are a part of the data model. Two kinds of integrity constraints are used in our work: referential integrity constraints and entity integrity constraints. As mentioned in Section 3.2.3, these integrity constraints are useful to reduce the number of left outer joins and non null filters. The ....

C. Date, "Referential Integrity," in Proc. 7th Int. Conf. Very Large Data Bases, Cannes, France, pp. 2-12, Sept. 1981.

No context found.

Date, C. Referential integrity. In G. Gardaun, M. Edelberg, C. Zaniolo, H. Biller, and C. Delobel (eds.), Proceedings of the Seventh International Conference on Very Large Data Bases. Cannes, France: VLDB, 1981, pp. 2--12.

No context found.

C. Date, Referential integrity, in: Proceedings of Intl. Conf. on Very Large Data Bases (VLDB), 1981, pp. 2--12.

No context found.

C. Date, Referential integrity, in: Proceedings of International Conference on Very Large Data Bases (VLDB), 1981, pp. 2--12.

No context found.

Date, C J `Referential Integrity' Proc. 7th Int. VLDB Conf. IEEE Computer Society Press (1981) pp 2-12

No context found.

Date, C.J. Referential Integrity, in Relational Database -- Selected Writings. Addison-Wesley (1986).

First 50 documents

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC