On the Power of Incremental Evaluation in SQL-like Languages
Leonid Libkin6
and Limsoon Wong7 
| (6) |
Bell Laboratories, 600 Mountain Avenue, 07974 Murray Hill, NJ, USA |
| (7) |
Kent Ridge Digital Labs, 21 Heng Mui Keng Terrace, 119613, Singapore |
Abstract
We consider IES(SQL), the incremental evaluation system over an SQL-like language with grouping, arithmetics, and aggregation. We show that every
second order query is in IES(SQL) and that there are PSPACE-complete queries in IES(SQL). We further show that every PSPACE query is in IES(SQL) augmented with a deterministic transitive closure operator. Lastly, we consider ordered databases and provide a complete
analysis of a hierarchy on IES(SQL) defined with respect to arity-bounded auxiliary relations.
Part of this work was done while visiting INRIA and Kent Ridge Digital Labs.
Part of this work was done while visiting Bell Labs.
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