Database Reference
In-Depth Information
simple value contained in one of its relations, does it belong to the database
TA
as a single-attribute single-tuple relation?
10. Why do we provide the definition of equality of two database mappings at the
instance level only, and how does this fact generalize the Data Exchange frame-
work and the equivalence of the logic formulae used in SOtgds? Why can the
category semantics presented in the introduction be satisfied by the informa-
tion flux for a given instance mapping between two instance databases? Is the
empty information flux between two database instances (of a source and target
schema) equivalent to the fact that there is no mapping between them? How can
it be explained in the case of an integrity-constraint mapping for the database
schemas?
11. What is the relationship between the categorial symmetry applied to the
database mapping systems and the algorithm for decomposition of SOtgds?
Is the decomposition of the mappings with the empty information flux mean-
ingful? Is the decomposition of the integrity-constraints mappings meaningful?
Why is it useful to represent the database mapping systems by the graphs, from
the user point of view and from the semantic (denotational) point of view? Why
is the compositional property of the schema mappings so important, and which
relationship does it have with the compositional properties of the information
fluxes at the instance level of the database mappings? Is it a necessary condition
in order to obtain a denotational semantics of the database mappings based on
categories?
References
1. J.F. Adams,
Infinite Loop Spaces
(Princeton U. Press, Princeton, 1978)
2. J.C. Baez, J. Dofan, Categorification, in
Workshop on Higher Category Theory and Physics
,
March 28-30, ed. by E. Getzler, M. Kapranov (Northwestern University, Evanston, 1997)
3. J.M. Boardman, R.M. Vogt,
Homotopy Invariant Structures on Topological Spaces
. Lecture
Notes in Mathematics, vol. 347 (Springer, Berlin, 1973)
4. A. Corradini, A complete calculus for equational deduction in coalgebraic specification. Report
SEN-R9723, National Research Institute for Mathematics and Computer Science, Amsterdam
(1997)
5. R. Fagin, P.G. Kolaitis, L. Popa, W. Tan, Composing schema mappings: second-order depen-
dencies to the rescue. ACM Trans. Database Syst.
30
(4), 994-1055 (2005)
6. L. Libkin, C. Sirangelo, Data exchange and schema mappings in open and closed worlds, in
Proc. of PODS'08
, Vancuver, Canada (2008)
7. J.P. May,
Simplicial Objects in Algebraic Topology
(Van Nostrand, Princeton, 1968)
