Projects per year
Abstract
The Nested Relational Calculus (NRC) has been an influential high-level query language, providing power and flexibility while still allowing translation to standard SQL queries. It has also been used as a basis for language-integrated query in programming languages such as F#, Scala, and Links. However, SQL's treatment of incomplete information, using nulls and three-valued logic, is not compatible with `standard' NRC based on two-valued logic. Nulls are widely used in practice for incomplete data, but the question of how to accommodate SQL-style nulls and incomplete information in NRC, or integrate such queries into a typed programming language, appears not to have been studied thoroughly. In this paper we consider two approaches: an explicit approach in which option types are used to represent (possibly) nullable primitive types, and an implicit approach in which types are treated as possibly-null by default. We give translations relating the implicit and explicit approaches, discuss handling nulls in language integration, and sketch extensions of normalization and conservativity results.
Original language | English |
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Title of host publication | Proceedings of the 18th International Symposium on Database Programming Languages (DBPL 2021) |
Publisher | ACM |
Pages | 3-6 |
Number of pages | 4 |
ISBN (Electronic) | 978-1-4503-8646-3 |
DOIs | |
Publication status | Published - 16 Aug 2021 |
Event | 18th International Symposium on Database Programming Languages - Copenhagen, Denmark Duration: 16 Aug 2021 → 16 Aug 2021 https://sites.google.com/view/dbpl2021 |
Conference
Conference | 18th International Symposium on Database Programming Languages |
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Abbreviated title | DBPL 2021 |
Country/Territory | Denmark |
City | Copenhagen |
Period | 16/08/21 → 16/08/21 |
Internet address |
Keywords
- Nested relational calculus
- incomplete information
- nulls
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Skye-A programming language bridging theory and practice for scientific data curation
1/09/16 → 31/08/22
Project: Research
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Mechanising the metatheory of SQL with NULLS
UK central government bodies/local authorities, health and hospital authorities
1/08/17 → 31/03/18
Project: Research