... that can be made by querying a database system, and, in particular, look at which observations are valid for a particular database ... being merged. However we establish that one cannot, in general, find a meaningful binary merging operator which is associative, ...
Publication - huliganka - 07/03/2022 - 23:42 - 0 comments - 0 attachments
... over the target schema that satisfies the schema mapping. In general, a given source instance may have numerous different solutions. ...
Publication - hartung - 04/17/2013 - 12:16 - 0 comments - 1 attachment
... this challenge that have received considerable attention in recent years are data exchange and data integration. The study of data ... database schemas. Schema mappings are typically expressed in declarative languages based on logical formalisms and are chosen with two ...
Publication - cat - 04/17/2013 - 11:16 - 0 comments - 1 attachment
... A database view is a portion of the data structured in a way suitable to a specific on views must be translated into updates on the underlying database. This translation process in the relational model. The procedure is as follows: first, a “complete” ...
Publication - erhard - 04/17/2013 - 09:38 - 0 comments - 0 attachments
... 10 - 49 In this paper we present a formal model for the support of temporal schema versions in object-oriented databases. Its definition is partially based on a generic ...
Publication - fgrandi - 04/17/2013 - 08:49 - 0 comments - 0 attachments
... model is proposed for dynamic schema evolution (DSE) in objectbase systems (OBSs) that supports the fundamental concepts of ...
Publication - erhard - 04/17/2013 - 08:49 - 0 comments - 0 attachments
... 970.14 KB In relational databases a view definition is a query against the database, and ... materialization over a database may change as relations in the database undergo modificationsIn this paper a mechanism is proposed in which the view is materialized at all times The problem which this mechanism ...
Publication - cat - 04/17/2013 - 08:05 - 0 comments - 1 attachment
... XML documents that satisfy a given schema, e.g., a DTD. In this context, when a given update violates the schema, it might be the ... to be used by a data administrator who is an expert in the domain of application of the database, but who is not required to be a ...
Publication - cat - 04/17/2013 - 07:27 - 0 comments - 0 attachments
... 100 - 499 In this paper we describe a new approach to data integration which subsumes the ...
Publication - cat - 04/17/2013 - 07:16 - 0 comments - 0 attachments
... the algorithm is such that the SVD computation step has in practice good performance, which makes it feasible to perform clustering ...
Publication - salva - 04/17/2013 - 06:27 - 0 comments - 0 attachments
... are yet no mapping systems that support core computations. In this paper we introduce several new algorithms that contribute to bridge the ...
Publication - salva - 04/17/2013 - 06:05 - 0 comments - 0 attachments
... tools for automating it have been proposed and evaluated in the database community. Research in this area reveals that there is no single schema matcher that is guaranteed ...
Publication - avigal - 04/17/2013 - 02:05 - 0 comments - 1 attachment
... “model” is today considered as a promising technology in domains such as data and software engineering. In the field of model engineering, models are now viewed as firts-class ...
Publication - huliganka - 04/17/2013 - 00:49 - 0 comments - 1 attachment
... version and configuration management. Most previous work in change management has dealt with flat-file and relational data; we focus on hierarchically structured data. Since in many cases changes must be computed from old and new versions of the data, ...
Publication - huliganka - 04/17/2013 - 00:49 - 0 comments - 1 attachment
... databases, and version and configuration management. In this paper we focus on detecting meaningful changes in hierarchically structured data, such as nested-object data. This problem is ...
Publication - huliganka - 04/17/2013 - 00:38 - 0 comments - 1 attachment
... to the original one. This question was addressed in the literature with respect to those relational schemes that satisfy the so ... \"tractable\" We are able to test losslessness defined in such a way for a wide class of relational expressions and dependencies. An ...
Publication - huliganka - 04/17/2013 - 00:27 - 0 comments - 1 attachment
... A into B have long been known to be dual problems. In this paper, they are shown to be equivalent to finding a shortest/longest path in an edit graph. Using this perspective, a simple O(ND) time and space ...
Publication - huliganka - 04/16/2013 - 23:16 - 0 comments - 1 attachment
... the most important of which is that schemas are placed in a partial order that has bounded joins. This means that the merging ... that the merge of schemas is independent of the order in which they are considered --- a property not possessed by existing ...
Publication - huliganka - 04/16/2013 - 20:38 - 0 comments - 1 attachment
... A subtle problem of schema integration is considered in its general form, not bound to any particular category of schemas. The ... theory are established that apply to integrity problems in schema integration. The theory is illustrated by a particular category of ...
Publication - huliganka - 04/16/2013 - 19:27 - 0 comments - 1 attachment
... effect as applying successively the two schema mappings. In this paper, we give a rigorous semantics to the composition of schema ... We first study the important case of schema mappings in which the specification is given by a finite set of source-to-target ...
Publication - cat - 04/16/2013 - 19:16 - 0 comments - 1 attachment
... such applications by providing a database infrastructure in which a set of high-level algebraic operators, such as Match, Merge, and ... and develop novel algorithms for implementing them. In particular, we present an innovative algorithm based on fixpoint ...
Publication - cat - 04/16/2013 - 18:38 - 0 comments - 1 attachment
... of interest arises when S is the class of all instances, in which case an S-inverse is a global inverse. We focus on the important ... we show how to construct an S-inverse when one exists. In particular, we show how to construct a global inverse when one exists. ...
Publication - cat - 04/16/2013 - 18:27 - 0 comments - 1 attachment
... 676.21 KB In this article, we develop a relational algebra for metadata integration, ... where the number of relations and/or the number of columns in relations of the output varies dynamically with the input instance. Among ... generalized dynamic output schemas, where the values in any (fixed) number of input columns can determine output schemas.Further ...
Publication - cat - 04/16/2013 - 18:27 - 0 comments - 1 attachment
... parts of a given data collection play an important role in many database applications. In dynamic environments where data is updated, not only information provided by ...
Publication - cat - 04/16/2013 - 18:16 - 0 comments - 1 attachment
... is based on a classification of the constructs used in the known data model into a limited set of types Then on the basis of ... deriving \"good\" translations between schemes and more in general between models Finally we define the architecture and the ...
Publication - huliganka - 04/16/2013 - 15:49 - 0 comments - 1 attachment
