Name
Abstract | ||
|---|---|---|
We study functional and multivalued dependencies over SQL tables with NOT NULL constraints. Under a no-information interpretation of null values we develop tools for reasoning. We further show that in the absence of NOT NULL constraints the associated implication problem is equivalent to that in propositional fragments of Priest's paraconsistent Logic of Paradox. Subsequently, we extend the equivalence to Boolean dependencies and to the presence of NOT NULL constraints using Schaerf and Cadoli's S-3 logics where S corresponds to the set of attributes declared NOT NULL. The findings also apply to Codd's interpretation "value at present unknown" utilizing a weak possible world semantics. Our results establish NOT NULL constraints as an effective mechanism to balance the expressiveness and tractability of consequence relations, and to control the degree by which the existing classical theory of data dependencies can be soundly approximated in practice. |
Year | DOI | Venue |
|---|---|---|
2010 | 10.1145/1807085.1807126 | PODS |
Keywords | Field | DocType |
no-information interpretation,existing classical theory,associated implication problem,effective mechanism,sql table,s-3 logic,data dependency,consequence relation,null constraint,boolean dependency,possible worlds,null value,paraconsistent logic | SQL,Discrete mathematics,Data dependency,Multivalued dependency,Paraconsistent logic,Computer science,Theoretical computer science,Equivalence (measure theory),Dependency theory (database theory),Null (SQL),Possible world | Conference |
Citations | PageRank | References |
19 | 0.55 | 36 |
Authors | ||
2 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Sven Hartmann | 1 | 409 | 42.86 |
| Sebastian Link | 2 | 185 | 12.50 |