Theory

Defining the XML Schema Matching Problem for a Personal Schema Based Query Answering System

Authors: 
Smiljanic, M.; van Keulen, M.; Jonker, W.
Year: 
2004

XML brought several important qualities to data representation. Through the usage of tags, it
combined schema and data information. Tag nesting enabled a simple representation of hierarchical
relations. Such enrichments sparked off a new wave of research on how to improve querying
and searching of data within XML documents.
The Internet is practically an endless collection of data being used simultaneously by millions
of users. We expect that for a large part, this information will become available in XML. As such,

Multitemporal Conditional Schema Evolution

Authors: 
Jensen, OG; Bohlen, MH
Year: 
2004
Venue: 
Proc. 3rd ER-Workshop Evolution and Change in Data Management (ECDM 2004), LNCS 3289

Schema evolution is the ability of the database to respond to changes in the real world by allowing the schema to evolve. The multidimensional conditionally evolving schema(MD-CES) is a conceptual model for conditional schema changes, which modify the schema of those tuples that satisfy the change condition. The MD-CES is lossless and preserves schemas, but has an exponential space complexity. In this paper we restrict conditional schema changes to timestamp attributes.

Correct Schema Transformations.

Authors: 
Qian, X.
Year: 
1996
Venue: 
Proc. EDBT 1996, LNCS 1057

We develop a formal basis of correct schema transformations. Schemas are formalized as abstract data types, and correct schema transformations are formalized as information-preserving signature interpretations. Our formalism captures transformations of all schema components, making it possible to transform uniformly constraints and queries along with structures. In addition, our formalism captures schema transformations between different data models as easily as those within the same data...

Making Workflow Change Acceptable

Authors: 
Moor, A de; Jeusfeld, MA
Year: 
2001
Venue: 
Requirements Engineering

Information Integration Using Logical Views

Authors: 
Ullman, J.D.
Year: 
1997
Venue: 
Proc. of the 6th Int. Conf. on Database Theory (ICDT 1997)

A number of ideas concerning information-integration tools can be
thought of as constructing answers to queries using views that
represent the capabilities of information sources. We review the
formal basis of these techniques, which are closely related to
containment algorithms for conjunctive queries and/or Datalog
programs. Then we compare the approaches taken by AT&T Labs'
\"Information Manifold\" and the Stanford \"Tsimmis\"
project in these terms.

A General Formal Framework for Schema Transformation

Authors: 
McBrien, P.; Poulovassilis, A.
Year: 
1998
Venue: 
Data & Knowledge Engineering, Volume 28, Issue 1 (October 1998)

Several methodologies for integrating database schemas have been
proposed in the literature,
using various common data models (CDMs). As part of these
methodologies transformations
have been defined that map between schemas which are in some sense
equivalent.
This paper describes a general framework for formally underpinning
the schema transformation
process. Our formalism clearly identifies which transformations apply
for any instance
of the schema and which only for certain instances. We illustrate the
applicability of the

A semantic meta-modelling approach to schema transformation

Authors: 
Papazoglou, M.P.; Russell, N.
Year: 
1995
Venue: 
CIKM 1995, Baltimore MD, USA

This paper presents an intermediate meta-model that consists
of a set of generic meta-classes that capture and describe
the semantics of a variety of data models. A model is
described by a set of intermediate model meta-classes (organized
in the form of a directed acyclic graph (DAG) to
achieve extensibility y), while irtst antes of these meta-classes
are used to describe a schema in a given data model. The
proposed approach supports dynamic meta-schema comparison
and transformation by employing special-purpose transformation
rules.

Schema Translation between Heterogeneous Data Models in a Lattice Framework

Authors: 
Atzeni, P.; Torlone, R.
Year: 
1995
Venue: 
In Sixth IFIP TC-2 Working Conf. on Data Semantics (DS-6), Atlanta, Georgia, 1995

In this paper we study the problem of translating schemes between
different data models,
in a formal framework that refers to a wide range of models. We first
introduce a graphtheoretic
formalism that allows us to uniformly represent schemes and models,
to compare
different data models and to describe the behavior of basic
translations. The formalism
is based on a classification of the constructs used in the known data
model into a limited
set of types. Then, we study in this framework formal properties of
scheme translation

Management of Multiple Models in an Extensible Database Design Tool

Authors: 
Atzeni, P.; Torlone, R.
Year: 
1996
Venue: 
EDBT 1996, LNCS 1057

We describe the development of a tool called MDM for the
management of multiple models and the translation of database schemes
This tool can be at the basis of an integrated CASE environment supporting the analysis and design of information systems that allows different representations for the same data schemes
We first present a graph-theoretic framework that allows us to formally investigate desirable properties of schema translations
The formalism is based on a classification of the constructs used in the known data model into a limited set of types

Managing Schema Mappings in Highly Heterogeneous Environments

Authors: 
Velegrakis, Y
Year: 
2005
Venue: 
Dissertation, Univ. of Toronto

Integration, transformation, and translation of data is increasingly important for modern
information systems and e-commerce applications. Views, and more generally, transformation
specifications, or mappings, provide the foundation for many data transformation
applications.
Mappings are usually specified manually by data administrators that are familiar with
the semantics of the data and have a good knowledge of the transformation language. The
task of generating and managing mappings is laborious, time consuming and error-prone

Relational languages for metadata integration

Authors: 
Wyss, CM; Robertson, EL
Year: 
2005
Venue: 
ACM Transactions on Database Systems (TODS)

In this article, we develop a relational algebra for metadata integration, Federated Interoperable Relational Algebra (FIRA). FIRA has many desirable properties such as compositionality, closure, a deterministic semantics, a modest complexity, support for nested queries, a subalgebra equivalent to canonical Relational Algebra (RA), and robustness under certain classes of schema evolution.

A Model Theory for Generic Schema Management

Authors: 
Alagic, S.; Bernstein, P.A.
Year: 
2001
Venue: 
DBPL'01, Marino, Rome, September 2001

The core of a model theory for generic schema management is developed. This theory has two
distinctive features: it applies to a variety of categories of schemas, and it applies to transformations
of both the schema structure and its integrity constraints. A subtle problem of schema integration is
considered in its general form, not bound to any particular category of schemas. The proposed solution,
as well as the overall theory, is based entirely on schema morphisms that carry both structural and

Modeling and Merging Database Schemas

Authors: 
Kosky, A.S.
Year: 
1991

We define a general model for database schemas which is basically functional and supports specialisation relationships. Despite it's simplicity, our model is very general and expressive, so that database schemas and instances arising from a number of other data models can be translated into the model.

Maintenance of views

Authors: 
Shmueli, O; Itai, A
Year: 
1984
Venue: 
Proc. 1984 ACM SIGMOD

In relational databases a view definition is a query against the database, and a view materialization is the result of applying the view definition to the current database A view 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 addresses is how to quickly update the view in response to database changes A structure is maintained which provides information useful in minimizing the amount of work caused by updatesMethods are presented fo

Losslessness and semantic correctness of database schema transformation: another look at schema equivalence

Authors: 
Kobayashi, I
Year: 
1986
Venue: 
Information Systems

Transformations between two groups of relation schemata play important roles in a database environment. These transformations are used for obtaining normal form relation schemata, generating certain view schemata and deciding appropriate internal schemata. They are also related to the data translation between distinct data models and hence between distinct database management systems. Relations belonging to one group of schemata are usually maintained in computer storage, while those belonging to another group of schemata can be virtual.

Data integration by bi-directional schema transformation rules

Authors: 
McBrien, P; Poulovassilis, A
Year: 
2003
Venue: 
ICDE 2003

In this paper we describe a new approach to data integration which subsumes the previous approaches of local as view (LAV) and global as view (GAV). Our method, which we term both as view (BAV), is based on the use of reversible schema transformation sequences. We show how LAV and GAV view definitions can be fully derived from BAV schema transformation sequences, and how BAV transformation sequences may be partially derived from LAV or GAV view definitions.

Theoretical Aspects of Schema Merging

Authors: 
Buneman, P.; Davidson, S.; Kosky, A.
Year: 
1992
Venue: 
EDBT 1992, LNCS 580,

A general technique for merging database schemas is developed that
has a number
of advantages over existing techniques, the most important of which
is that schemas are
placed in a partial order that has bounded joins. This means that the
merging operation,
when it succeeds, is both associative and commutative, i.e., that the
merge of schemas
is independent of the order in which they are considered --- a
property not possessed by
existing methods. The operation is appropriate for the design of
interactive programs as it

On the computation of relational view complements

Authors: 
Lechtenboerger, J.; Vossen, G.
Year: 
2003
Venue: 
VLDBJ

Views as a means to describe 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 views, but also information provided by data sources yet missing from views turns out to be relevant: Previously, this missing information has been characterized in terms of view complements; recently, it has been shown that view complements can be exploited in the context of data warehouses to guarantee desirable warehouse properties such as independence and self-maintainability.

Inverting Schema Mappings

Authors: 
Fagin, R.
Year: 
2006
Venue: 
Proc. PODS 2006

A schema mapping is a specification that describes how data
structured under one schema (the source schema) is to be
transformed into data structured under a different schema
(the target schema). Although the notion of an inverse of
a schema mapping is important, the exact definition of an
inverse mapping is somewhat elusive. This is because a
schema mapping may associate many target instances with
each source instance, and many source instances with each
target instance. Based on the notion that the composition
of a mapping and its inverse is the identity, we give a formal

Composing Schema Mappings: Second-Order Dependencies to the Rescue

Authors: 
Fagin, R.; Kolaitis, P.G.; Popa, L.; Tan, W.C.
Year: 
2004
Venue: 
PODS 2004, TODS 2005

A schema mapping is a specification that describes how data structured under one schema (the
source schema) is to be transformed into data structured under a different schema (the target
schema). A fundamental problem is composing schema mappings: given two successive schema
mappings, derive a schema mapping between the source schema of the first and the target schema
of the second that has the same effect as applying successively the two schema mappings.
In this paper, we give a rigorous semantics to the composition of schema mappings and investigate

Generic Model Management: Concepts and Algorithms

Authors: 
Melnik, S.
Year: 
2004
Venue: 
Dissertation, Univ. of Leipzig, 2004

Many challenging problems facing information systems engineering involve
the manipulation of complex metadata artifacts, or models, such as database
schemas, interface specifications, or object diagrams, and mappings between
models. The applications that solve metadata manipulation problems are
complex and hard to build. The goal of generic model management is to
reduce the amount of programming needed to develop such applications by
providing a database infrastructure in which a set of high-level algebraic
operators, such as Match, Merge, and Compose, are applied to models and

A Theory of Attributed Equivalence in Databases with Application to Schema Integration

Authors: 
Larson, J. A.; Navathe, S. B.; Elmasri, R.
Year: 
1989
Venue: 
IEEE Transactions on Software Engineering, 1989

The authors present a common foundation for integrating pairs of entity sets, pairs of relationship sets, and an entity set with a relationship set. This common foundation is based on the basic principle of integrating attributes. Any pair of objects whose identifying attributes can be integrated can themselves be integrated. Several definitions of attribute equivalence are presented. These definitions can be used to specify the exact nature of the relationship between a pair of attributes. Based on these definitions, several strategies for attribute integration are presented and evaluated.

Semantics of Database Transformations

Authors: 
Davidson, Susan; Buneman, Peter; Kosky, Anthony
Year: 
1998
Venue: 
LNCS 1358, 1998

Database transformations arise in many different settings including
database integration, evolution of database systems, and implementing user views
and data entry tools. This paper surveys approaches that have been taken to problems in these settings, assesses their strengths and weaknessesd
develops requirements on a formal model for specifying and implementing database transformations. We also consider the problem of insuring the correctness of database transforma
tions
In particular, we demonstrate that the usefulness of correctness conditions

Update Semantics of Relational Views

Authors: 
Bancilhon, F.; Spyratos, N.,
Year: 
1981
Venue: 
TODS, 1981

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” set of updates is defined such
(i) together with every update the set contains a “return” update, that is, one
back to the original state;
(ii) given two updates in the set, their composition is also in the set.
To translate a complete set, we define a mapping called a “translator,” that

An Axiomatic Model of Dynamic Schema Evolution in Objectbase Systems

Authors: 
Peters, Randel J.; Özsu, M. Tamer
Year: 
1997
Venue: 
ACM TODS 22(1): 75-114 (1997)

A sound and complete axiomatic model is proposed for dynamic schema evolution (DSE) in objectbase systems (OBSs) that supports the fundamental concepts of object-oriented computing such as subtyping and property inheritance. The model can infer all schema relationships from two identified input sets associated with each type called the essential supertypes and essential properties. These sets are typically specified by schema designers but can be automatically supplied within an OBS. The inference mechanism performed by the model has a proven termination.

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