Results 1 to 10 of about 4,932 (93)
On covering Boyce-Codd normal forms
Information Processing Letters, 1980 In the relational model of data the Boyce-Codd-Heath normal form, commonly just known as Boyce-Codd normal form, guarantees the elimination of data redundancy in terms of functional dependencies. For efficient means of data processing the industry standard SQL permits partial data and duplicate rows of data to occur in database systems.
Peter Kandzia, Margret Mangelmann
exaly +7 more sources
Survival of contagious ovine digital dermatitis (CODD)-associated treponemes on disposable gloves after handling CODD-affected feet [PDF]
Veterinary Record, 2017 Both contagious ovine digital dermatitis (CODD) and bovine digital dermatitis (BDD) are causes of infectious lameness in sheep and cattle, respectively, and are strongly associated with the presence of specific treponemes, with three different cultivable phylogroups commonly isolated: Treponema medium
Nicholas J. Evans +2 more
exaly +4 more sources
On the Codd semantics of SQL nulls [PDF]
Information Systems, 2019 Abstract Theoretical models used in database research often have subtle differences with those occurring in practice. One particular mismatch that is usually neglected concerns the use of marked nulls to represent missing values in theoretical models of incompleteness, while in an SQL database these are all denoted by the same syntactic object ...
Paolo Guagliardo, Leonid Libkin
openaire +3 more sources
Codd's Self-Replicating Computer [PDF]
Artificial Life, 2010 Edgar Codd's 1968 design for a self-replicating cellular automaton has never been implemented. Partly this is due to its enormous size, but we have also identified four problems with the original specification that would prevent it from working. These problems potentially cast doubt on Codd's central assertion, that the eight-state space he presents ...
openaire +3 more sources
Codd's Theorem for Databases over Semirings
Proceedings of the ACM on Management of DataCodd's Theorem, a fundamental result of database theory, asserts that relational algebra and relational calculus have the same expressive power on relational databases. We explore Codd's Theorem for databases over semirings and establish two different versions of this result for such databases: the first version involves the five basic operations of ...
Guillermo Badia +2 more
openaire +5 more sources
Fehlererkennende Registermaschinen in Codd's Zellularraum
, 1984 Am Beispiel von Codd's Raum wird gezeigt, wie sich das berechnungsuniverselle Konzept von Registermaschinen in einem Zellularraum so implementieren läßt, daß beim Lösen rekursiver Aufgaben erreichte Zellen selbstätig auf Defekte getestet und mögliche Rechenfehler erkannt werden.
Wachsmuth, Ipke +2 more
openaire +1 more source
On the Codd Semantics of SQL Nulls
, 2017 Theoretical models used in database research often have subtle differences with those occurring in practice. One particular mismatch that is usually neglected concerns the use of marked nulls to represent missing values in theoretical models of incompleteness, while in an SQL database these are all denoted by the same syntactic NULL object.
Guagliardo, Paolo; id_orcid 0000-0003-0756-5787 +1 more
openaire +1 more source