Larson, J.A., Navathe, S.B., Elmasri, R.: A theory of attribute equivalence in databases with application to schema integration. IEEE Trans. Software Eng. 15 (1989) 449--463  Home/Search   Document Not in Database   Summary   Related Articles   Check

....model, then any model, our Merge allows for some preferences to be made once per Merge rather than at each mapping relationship. 8.2. 2 View Integration View integration is the problem of combining multiple user views into a unified schema [3] This problem has been studied in many contexts [4, 5, 8, 11, 18, 28, 29]. View integration algorithms (1) ensure the merged model contains all of the objects in the two original models, 2) reconcile representation conflicts in the views (e.g. if a table in one view is matched with a column in another) and (3) require user input to guide the merge. Spaccapietra and ....

Larson, J.A., Navathe, S.B. and Elmasri, R. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. Trans. on Soft. Eng., 15(4). 449-463.

....requiting immediate updates. Both correspond to the redundancy dependency with respect to copies that have to be held consistent. Our approach also discovers possible redundant data by duplicated schema elements. A theory of attribute equivalence in databases on a semantic basis is presented in [LNE89]. The approach uses semantic attribute equivalence for integration of database schemas. Therefore the characteristics of the attribute equivalence are very demiled and restrictive. In contrast to schema integration, schema reverse engineering needs flexible and general attribute property ....

J.A. Larson, S.B. Navathe, and R. Elmasri. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. IEEE Transactions on Software Engineering, 15(4):449-463, IEEE Computer Society Press, April 1989.

....each object is allowed to have at most one type, then m 3 manifests a constraint violation that must be repaired, either as part of Merge or in a postprocessing step. A solution to this specific problem appears in [9] A more general discussion of constraint violations in merge results appears in [15]. 3.4 Compose The composition operator, represented by . creates a mapping by combining two other mappings. If map 1 relates models M 1 and M 2 , and map 2 relates M 2 and M 3 , then the composition map 3 = map 2 . map 1 is a mapping that relates M 1 and M 3 (i.e. map 3 (M 1 ) map 2 (map 1 ....

....that can be studied as challenges for the model management operators. This literature is too large to cite here, but we can highlight a few areas where there is obvious synergy worth exploring. Some of them were mentioned earlier: schema matching (see the survey in [23] schema integration [1,8,15,25], which is both an example and a source of algorithms for Match and Merge; and adding semantics to mappings [7,17,21,27] Others include: Data translation [24] Differencing [11,19,26] and . EER style representations and their expressive power, which may help select the best representation ....

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Larson, James A., Shamkant B. Navathe, and Ramez Elmasri. A theory of attribute equivalence in databases with application to schema integration. Trans. on Soft. Eng. 15(4):449-463 (April 1989).

....and local ontologies. The COIN [5] project presents a suitable architecture for semantic interoperability. The role of the Domain Model in the COIN architecture can be compared to that of an ontology. However, the Domain Model is rather close to a conceptual model. Work of Larson et.al in [10] is very close to this work. This paper address some challenges already addressed in [10] However, an important difference is that we distinguish and emphasize the difference between the ontological characteristics of attributes and its representational and implementational characteristics. For ....

....interoperability. The role of the Domain Model in the COIN architecture can be compared to that of an ontology. However, the Domain Model is rather close to a conceptual model. Work of Larson et.al in [10] is very close to this work. This paper address some challenges already addressed in [10]. However, an important difference is that we distinguish and emphasize the difference between the ontological characteristics of attributes and its representational and implementational characteristics. For example, characteristics such as domain, uniqueness, cardinality are present in the ....

James A. Larson, Shamkant B. Navathe, and Ramez Elmasri. A theory of attribute equivalence in database with application to schema integration. IEEE Transactions on Software Engineering, 15(4):449--463, April 1989.

....types of publications. Fig. 1 depicts the corresponding schemas of both databases. Before these schemas are integrated, conflicts have to be resolved. Here we consider extensional and intensional conflicts only. We assume that other types of conflicts are resolved before as described, e.g. in [LNE89, SPD92] Extensional conflicts refer to potential object redundancies among different classes whereas intensional conflicts are caused by different object types of semantically related classes. The schemas define extensional subset relationships between sub and superclasses and relationships due ....

....which is stored in the library or in the project database (or in both) can be assigned to exactly one base extension. Now we have to compare the intensional aspects of the two schemas. For simplicity, we assume attributes with same names have identical semantics, i.e. attribute conflicts [LNE89] are assumed to be resolved before. From the given extensional and intensional information we can automatically derive a table that assigns attributes to base extensions. A tick symbol for a column (base extension) and a row (attribute) means that for potential objects of that base extension we ....

J. A. Larson, S. B. Navathe, and R. Elmasri. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. IEEE Transactions on Software Engineering, 15(4):449--463, April 1989.

....not just with metadata in the views. There has been a large amount of work in the integration area: a detailed survey by Batini et al. 2] discusses 12 methodologies for view or database integration (or both) and new contributions continuously appear in the literature [3] 4] 5] 6] 7] [8] [9] 10] As view integration is a process in which knowledge of the semantics of data is needed, it is no surprise that most of the current methodologies rely on a semantic data modelling approach. In particular, the Entity Relationship (ER) approach, in its various extended forms, represents ....

....current ER methodologies are restricted to integrate entities with entities, relationships with relationships and attributes with attributes. This is similar to what a relational approach may achieve using various interrelational dependencies [16] 17] 18] One limited exception may be found in [8], where the authors integrate an entity type with a relationship type, under the very restrictive hypothesis that the key of the entity type is the aggregate of the keys of the entity types participating in the relationship. This paper proposes an integration methodology, designed to be able to: ....

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J. A. Larson, S. B. Navathe, R. Elmasri, "A Theory of Attribute Equivalence in Databases with Application to Schema Integration", IEEE Transactions On Software Engineering, Vol. SE-15, n4, April 1989

....obliged to reason about the objects themselves (in addition to reasoning about the values that represent the objects) in order to establish the meaning of the mapping. For this reason we introduce the notion of Real World State (RWS) This notion has been used with different shades of distinction [13, 17]. In our case we use it in the following way: to define the constraints that a mapping between a terminology and a relational view must satisfy. Mapping among Knowledge Bases and Data Repositories: Precise Definition of its Syntax and Semantics 281 ID Name Address Phone StartingDate : ....

J. A. Larson, S. B. Navathe, and R. Elmasri. A theory of attribute equivalence in databases with application to schema integration. IEEE TOSE, SE-15(4):449-463 (1989).

....assertions among different component schemas to compare attributes and entity types. In [20] interschema assertions, names, and types are used to compare object types. In [18] schemas are merged using schema operators and assertions among entity types and attributes in different schemas. And in [16], attribute assertions (e.g. key non key and lower upper bounds) are used to compare attributes and entity types. However, the assertions must be supplied by the designer and the resolution of conflicts strongly depends on the common sense of the designer. Other methods use schema transformations ....

J. Larson, S. Navathe, and R. Elmasri. A theory of attribute equivalence in databases with application to schema integration. IEEE Transactions on Software Engineering, 15(4):449-- 463, 1989.

....schema integration has been carried out since the beginning of the 1980s. A comprehensive survey of the area can be found in [Batini86] Most of the 3 work has been done in the context of the relational model [Biskup86] the functional model [Motro87] or (some extended version of) the ER model, [Larson89], Spaccapietra92] Johannesson93a] Johannesson93b] Johannesson93c] Most work has focused on how to merge a number of schemas given a set of proposed schema correspondences. In recent years, however, several researchers have also shown an interest in heuristic methods for identifying ....

J. A. Larson, S. Navathe and R. ElMasri, "A Theory of Attribute Equivalence in Databases with Apllications to Schema Integration", IEEE Transactions on Software Engineering, vol. 15, no. 4, pp. 449-463, 1989.

....can be resolved by transforming the local schemata into the canonical data model of the FDBS. In the second step schematic heterogeneity is solved. In general, this step is a very complex task due to many kinds of conflicts. Therefore, different integration methodologies were proposed in [2, 12, 21, 7, 15, 14]. There are different requirements attributed to the integration of local schemata into an integrated schema (adopted from [2] page 337) ffl Completeness and Correctness : The integrated schema must contain all concepts present in any component schema correctly. The integrated schema must be a ....

....all new buildings (S1.Buildings not specialized to old buildings) are included in the second database as habitable buildings. S1.Building: S1.Old Building: S2.Building: S2.Habitable Building: 1 2 3 4 5 Figure 2: Extensional Overlapping of Input Classes Most existing integration approaches [13, 12, 21, 3, 7, 22, 15, 8, 14] do only mark pairs of classes with a possibly non empty population intersection as candidates for integration. Additionally, attributes may be marked to be corresponding. The resulting integration assertions can be listed in the notation proposed by [22] S1fflBuilding S2fflBuilding ....

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J.A. Larson, S.B. Navathe, R. Elmasri. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. IEEE Transactions on Software Engineering, 15(4):449--463, 1989.

....during the integration of different schemata is how to correctly deal with the heterogeneity. Data model heterogeneity can be resolved by transforming each local schema into the canonical data model. After that schema heterogeneity has to be overcome. Many methodologies were proposed (e.g. BLN86, LNE89, SPD92, Dup94, RPRG94, PBE95] which describe various conflict resolution techniques. In order to support logical data independence, different external schemata must be derivable from the integrated schema. From now on, we refer to such views as external integrated schemata. The generation of a ....

....of conflicts is given in [SK93, Kim95] 3 For our discussion, we use a very simplified example focusing on the problem of solving extensional and intensional overlappings. We assume that other conflicts are resolved (e.g. naming conflicts, meta conflicts [KLK91, CL94] and attribute conflicts [LNE89] Both example schemata are object oriented, and attributes with identical name have identical semantics. The example schemata are taken from a library application and from a university administration, respectively (see Figure 1) The filled subclass symbol denotes a non exclusive specialization ....

J.A. Larson, S.B. Navathe, and R. Elmasri. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. IEEE Transactions on Software Engineering, 15(4):449--463, 1989.

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Larson, J.A., Navathe, S.B., Elmasri, R.: A theory of attribute equivalence in databases with application to schema integration. IEEE Trans. Software Eng. 15 (1989) 449--463

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Larson, J.A., Navathe, S.B., Elmasri, R.: A theory of attribute equivalence in databases with application to schema integration. IEEE Trans. Software Eng. 15 (1989) 449--463

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Larson, J.A., Navathe, S.B., Elmasri, R.: A theory of attribute equivalence in databases with application to schema integration. IEEE Trans. Software Eng. 15 (1989) 449--463

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J. A. Larson, S. B. Navathe, and R. Elmasri. A theory of attribute equivalence in databases with application to schema integration. IEEE TOSE, SE-15(4), April 1989. 5

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J. A. Larson, S. B. Navathe, and R. Elmasri. A theory of attribute equivalence in databases with application to schema integration. IEEE TOSE, SE-15(4):449-463 (1989).

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J. A. Larson, S. B. Navathe, and R. Elmasri. A theory of attribute equivalence in databases with application to schema integration. IEEE TOSE, SE-15(4), April 1989.

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James A. Larson, Shamkant B. Navathe, and Ramez Elmasri. A theory of attribute equivalence in databases with application to schema integration. Transactions on Software Engineering, 15(4):449-463, April 1989.

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James A. Larson, Shamkant B. Navathe, and Ramez Elmasri. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. IEEE Transactions on Software Engineering, 15(4):449--463, April 1989.

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J. Larson, S. Navathe, and R. Elmasri. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. IEEE Transactions on Software Engineering, 15(4):449--463, April 1989.

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James A. Larson, Shamkant B. Navathe, and Ramez Elmasri. A theory of attribute equivalence in databases with application to schema integration. Transactions on Software Engineering, 15(4):449-463, April 1989.

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J.A. Larson, S.B. Navathe, and R. Elmastri, A theory of attribute equivalence in databases with application to schema integration, IEEE Transactions on Software Engineering, 15(4):449-463, 1989.

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James A. Larson, S. B. Navathe and R. Elmasri, "A Theory of Attribute Equivalence in Databases with Application to Schema Integration," IEEE Transactions on Software Engineering, 15, 4, (1989), pp. 449-463.

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J. Larson, S. Navathe, and R. Elmasri. A theory of attribute equivalence in databases with application to schema integration. IEEE Transactions on Software Engineering, 15(4), 1989.

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J. A. Larson, S. B. Navathe, R. Elmasri. A Theory of Attribute Equivalence in Databases with Application to Schema Integration. IEEE Transactions on Software Engineering, 15#4#:449#463, 1989.

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