Incomplete Information in Relational Databases
Journal of the ACM (JACM)
Answering recursive queries using views
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Horn clauses and database dependencies
Journal of the ACM (JACM)
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Optimization Properties for Classes of Conjunctive Regular Path Queries
DBPL '01 Revised Papers from the 8th International Workshop on Database Programming Languages
MiniCon: A scalable algorithm for answering queries using views
The VLDB Journal — The International Journal on Very Large Data Bases
Answering queries using views: A survey
The VLDB Journal — The International Journal on Very Large Data Bases
The Piazza Peer Data Management System
IEEE Transactions on Knowledge and Data Engineering
Generic Model Management: Concepts And Algorithms (Lecture Notes in Computer Science)
Generic Model Management: Concepts And Algorithms (Lecture Notes in Computer Science)
Locally consistent transformations and query answering in data exchange
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Composition of mappings given by embedded dependencies
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Supporting executable mappings in model management
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
Composing schema mappings: Second-order dependencies to the rescue
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2004
Nested mappings: schema mapping reloaded
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Model management 2.0: manipulating richer mappings
Proceedings of the 2007 ACM SIGMOD international conference on Management of data
Quasi-inverses of schema mappings
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On reconciling data exchange, data integration, and peer data management
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
ACM Transactions on Database Systems (TODS)
Composing mappings among data sources
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
The recovery of a schema mapping: bringing exchanged data back
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Towards a theory of schema-mapping optimization
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Structural characterizations of schema-mapping languages
Proceedings of the 12th International Conference on Database Theory
Composing local-as-view mappings: closure and applications
Proceedings of the 13th International Conference on Database Theory
Foundations of schema mapping management
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Composition and inversion of schema mappings
ACM SIGMOD Record
Relaxed notions of schema mapping equivalence revisited
Proceedings of the 14th International Conference on Database Theory
Reverse data exchange: Coping with nulls
ACM Transactions on Database Systems (TODS)
ACM SIGMOD Record
Data exchange beyond complete data
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Use of schema associative mapping for synchronization of the virtual machine audit logs
CISIS'11 Proceedings of the 4th international conference on Computational intelligence in security for information systems
Local transformations and conjunctive-query equivalence
PODS '12 Proceedings of the 31st symposium on Principles of Database Systems
Query language-based inverses of schema mappings: semantics, computation, and closure properties
The VLDB Journal — The International Journal on Very Large Data Bases
Value invention in data exchange
Proceedings of the 2013 ACM SIGMOD International Conference on Management of Data
The language of plain SO-tgds: Composition, inversion and structural properties
Journal of Computer and System Sciences
Data exchange beyond complete data
Journal of the ACM (JACM)
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The inversion of schema mappings has been identified as one of the fundamental operators for the development of a general framework for metadata management. In fact, during the last years three alternative notions of inversion for schema mappings have been proposed (Fagin-inverse [10], quasi-inverse [14] and maximum recovery [2]). However, the procedures that have been developed for computing these operators have some features that limit their practical applicability. First, these algorithms work in exponential time and produce inverse mappings of exponential size. Second, these algorithms express inverses in some mappings languages which include features that are difficult to use in practice. A typical example is the use of disjunction in the conclusion of the mapping rules, which makes the process of exchanging data much more complicated. In this paper, we propose solutions for the two problems mentioned above. First, we provide a polynomial time algorithm that computes the three inverse operators mentioned above given a mapping specified by a set of tuple-generating dependencies (tgds). This algorithm uses an output mapping language that can express these three operators in a compact way and, in fact, can compute inverses for a much larger class of mappings. Unfortunately, it has already been proved that this type of mapping languages has to include some features that are difficult to use in practice and, hence, this is also the case for our output mapping language. Thus, as our second contribution, we propose a new and natural notion of inversion that overcomes this limitation. In particular, every mapping specified by a set of tgds admits an inverse under this new notion that can be expressed in a mapping language that slightly extends tgds, and that has the same good properties for data exchange as tgds. Finally, as our last contribution, we provide an algorithm for computing such inverses.