On the Logic of SQL Nulls

  title={On the Logic of SQL Nulls},
  author={Enrico Franconi and Sergio Tessaris},
The logic of nulls in databases has been subject of investigation since their introduction in Codd’s Relational Model, which is the foundation of the SQL standard. In the logic based approaches to modelling relational databases proposed so far, nulls are considered as representing unknown values. Such existential semantics fails to capture the behaviour of the SQL standard. We show that, according to Codd’s Relational Model, a SQL null value represents a non-existing value; as a consequence no… CONTINUE READING


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Database Explorations: Essays on the Third Manifesto and Related Topics

  • C. J. Date, H. Darwen
  • Trafford Publishing
  • 2010
Highly Influential
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