Distributed databases principles and systems
Distributed databases principles and systems
An introduction to database systems: vol. I (4th ed.)
An introduction to database systems: vol. I (4th ed.)
Relational database: selected writings
Relational database: selected writings
Optimization of nested SQL queries revisited
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Query processing techniques in the summary-table-by-example database query language
ACM Transactions on Database Systems (TODS)
Optimization and dataflow algorithms for nested tree queries
VLDB '89 Proceedings of the 15th international conference on Very large data bases
A polygon model for heterogeneous database systems: the source tagging perspective
Proceedings of the sixteenth international conference on Very large databases
Federated database systems for managing distributed, heterogeneous, and autonomous databases
ACM Computing Surveys (CSUR) - Special issue on heterogeneous databases
Query graphs, implementing trees, and freely-reorderable outerjoins
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Formal semantics of SQL queries
ACM Transactions on Database Systems (TODS)
Oracle/SQL: a professional programmer's guide
Oracle/SQL: a professional programmer's guide
Advanced capabilities of the outer join
ACM SIGMOD Record
Algebraic optimization of outerjoin queries
Algebraic optimization of outerjoin queries
Outerjoin optimization in multidatabase systems
DPDS '90 Proceedings of the second international symposium on Databases in parallel and distributed systems
The functional data model and the data languages DAPLEX
ACM Transactions on Database Systems (TODS)
Extending the database relational model to capture more meaning
ACM Transactions on Database Systems (TODS)
How to Extend a Conventional Optimizer to Handle One- and Two-Sided Outerjoin
Proceedings of the Eighth International Conference on Data Engineering
Extending the Algebraic Framework of Query Processing to Handle Outerjoins
VLDB '84 Proceedings of the 10th International Conference on Very Large Data Bases
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
ACM SIGMOD Record
Theory of Relational Databases
Theory of Relational Databases
Hypergraph based reorderings of outer join queries with complex predicates
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
SQL query optimization: reordering for a general class of queries
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Integrating information by outerjoins and full disjunctions (extended abstract)
PODS '96 Proceedings of the fifteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Outerjoin simplification and reordering for query optimization
ACM Transactions on Database Systems (TODS)
Queries with incomplete answers over semistructured data
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Data-driven understanding and refinement of schema mappings
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
The EVE Approach: View Synchronization in Dynamic Distributed Environments
IEEE Transactions on Knowledge and Data Engineering
Schema Mapping as Query Discovery
VLDB '00 Proceedings of the 26th International Conference on Very Large Data Bases
Querying Semantically Tagged Documents on the World-Wide Web
NGIT '99 Proceedings of the 4th International Workshop on Next Generation Information Technologies and Systems
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Canonical abstraction for outerjoin optimization
SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
An incremental algorithm for computing ranked full disjunctions
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
View matching for outer-join views
VLDB '05 Proceedings of the 31st international conference on Very large data bases
Full disjunctions: polynomial-delay iterators in action
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
View matching for outer-join views
The VLDB Journal — The International Journal on Very Large Data Bases
An incremental algorithm for computing ranked full disjunctions
Journal of Computer and System Sciences
Maximally joining probabilistic data
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Partition search for non-binary constraint satisfaction
Information Sciences: an International Journal
Matching twigs in probabilistic XML
VLDB '07 Proceedings of the 33rd international conference on Very large data bases
Generating all maximal induced subgraphs for hereditary and connected-hereditary graph properties
Journal of Computer and System Sciences
ACM Computing Surveys (CSUR)
Modeling and querying probabilistic XML data
ACM SIGMOD Record
Computing full disjunction using COJO
Information Technology and Management
International Journal of Metadata, Semantics and Ontologies
Data fusion: resolving data conflicts for integration
Proceedings of the VLDB Endowment
Subsumption and complementation as data fusion operators
Proceedings of the 13th International Conference on Extending Database Technology
Querying a super-peer in a schema-based super-peer network
DBISP2P'05/06 Proceedings of the 2005/2006 international conference on Databases, information systems, and peer-to-peer computing
ITREKS: keyword search over relational database by indexing tuple relationship
DASFAA'07 Proceedings of the 12th international conference on Database systems for advanced applications
Immediate materialized views with outerjoins
DOLAP '10 Proceedings of the ACM 13th international workshop on Data warehousing and OLAP
Aggregated search of data and services
Information Systems
MapMerge: correlating independent schema mappings
Proceedings of the VLDB Endowment
CBMS'03 Proceedings of the 16th IEEE conference on Computer-based medical systems
Combining incompleteness and ranking in tree queries
ICDT'07 Proceedings of the 11th international conference on Database Theory
An abstract framework for generating maximal answers to queries
ICDT'05 Proceedings of the 10th international conference on Database Theory
Virtual integration of existing web databases for the genotypic selection of cereal cultivars
ODBASE'06/OTM'06 Proceedings of the 2006 Confederated international conference on On the Move to Meaningful Internet Systems: CoopIS, DOA, GADA, and ODBASE - Volume Part I
Declarative data fusion – syntax, semantics, and implementation
ADBIS'05 Proceedings of the 9th East European conference on Advances in Databases and Information Systems
Incremental maintenance of materialized views with outerjoins
Information Systems
MapMerge: correlating independent schema mappings
The VLDB Journal — The International Journal on Very Large Data Bases
Wondering why data are missing from query results?: ask conseil why-not
Proceedings of the 22nd ACM international conference on Conference on information & knowledge management
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The outerjoin operator is currently available in the query language of several major DBMSs, and it is included in the proposed SQL2 standard draft. However, “associativity problems” of the operator have been pointed out since its introduction. In this paper we propose a shift in the intuition behind outerjoin: Instead of computing the join while also preserving its arguments, outerjoin delivers tuples that come either from the join or from the arguments. Queries with joins and outerjoins deliver tuples that come from one out of several joins, where a single relation is a trivial join. An advantage of this view is that, in contrast to preservation, disjunction is commutative and associative, which is a significant property for intuition, formalisms, and generation of execution plans.Based on a disjunctive normal form, we show that some data merging queries cannot be evaluated by means of binary outerjoins, and give alternative procedures to evaluate those queries. We also explore several evaluation strategies for outerjoin queries, including the use of semijoin programs to reduce base relations.