## Abstract

Full disjunctions are an associative extension of the outerjoin operator to an arbitrary number of relations. Their main advantage is the ability to maximally combine data from different relations while preserving all the original information. An algorithm for efficiently computing full disjunctions is presented. This algorithm is superior to previous ones in three ways. First, it is the first algorithm that computes a full disjunction with a polynomial delay between tuples. Hence, it can be implemented as an iterator that produces a stream of tuples, which is important in many cases (e.g., pipelined query processing and Web applications). Second, the total runtime is linear in the size of the output. Third, the algorithm employs a novel optimization that divides the relation schemes into biconnected components, uses a separate iterator for each component and applies outerjoins whenever possible. Combining efficiently full disjunctions with standard SQL operators is discussed. Experiments show the superiority of our algorithm over the state of the art.

Original language | English |
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Title of host publication | VLDB 2006 - Proceedings of the 32nd International Conference on Very Large Data Bases |

Publisher | Association for Computing Machinery |

Pages | 739-750 |

Number of pages | 12 |

ISBN (Print) | 1595933859, 9781595933850 |

State | Published - 2006 |

Externally published | Yes |

Event | 32nd International Conference on Very Large Data Bases, VLDB 2006 - Seoul, Korea, Republic of Duration: 12 Sep 2006 → 15 Sep 2006 |

### Publication series

Name | VLDB 2006 - Proceedings of the 32nd International Conference on Very Large Data Bases |
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### Conference

Conference | 32nd International Conference on Very Large Data Bases, VLDB 2006 |
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Country/Territory | Korea, Republic of |

City | Seoul |

Period | 12/09/06 → 15/09/06 |

### Bibliographical note

Publisher Copyright:Copyright 2006 VLDB Endowment, ACM