TY  - JOUR
A1  - Desharnais, Jules
A1  - Möller, Bernhard
T1  - The theta-join as a join with theta
T2  - Lecture Notes in Computer Science
N2  - We present an algebra for the classical database operators. Contrary to most approaches we use (inner) join and projection as the basic operators. Theta joins result by representing theta as a database table itself and defining theta-join as a join with that table. The same technique works for selection. With this, (point-free) proofs of the standard optimisation laws become very simple and uniform. The approach also applies to proving join/projection laws for preference queries. Extending the earlier approach of [16], we replace disjointness assumptions on the table types by suitable consistency conditions.  Selected results have been machine-verified using the CALCCHECK tool.
Y1  - 2020
UR  - https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/91143
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-911436
SN  - 0302-9743
SN  - 1611-3349
N1  - Relational and Algebraic Methods in Computer Science: 18th International Conference, RAMiCS 2020, Palaiseau, France, October 26–29, 2020, Proceedings
VL  - 12062
SP  - 47
EP  - 64
PB  - Springer
CY  - Cham
ER  -