Optimization of nested SQL queries revisited

SQL Nested Queries in SPARQL

SPARQL currently does not include any form of nested queries. In this paper we present a proposal to incorporate nested queries into SPARQL along the design philosophy of SQL nested queries. We present rewriting algorithms and show that all the proposed nested queries can be expressed in a natural and simple extension of SPARQL syntax.

Optimization of Nested SQL

We present a new optimization method for nested SQL query blocks with aggregation operators. The method is derived from the theory of dependency implication. It uniies and generalizes previously proposed (seemingly unrelated) algorithms, and can incorporate general database dependencies given in the database schema. We apply our method to query blocks with max, min aggregation operators. We obt...

Translation of SQL Queries Containing Nested Predicated into Pseudonatural Language

An approach to support query verification by translating SQL queries into easy-to-read pseudonatural language expressions is proposed. The method discussed here converts various types of SQL queries, including simple and composite nested ones. Since it employs no complex natural language processing technique, it is feasible even on small computers.

Test-Case Generation for SQL Nested Queries with Existential Conditions

This paper presents a test-case generator for SQL queries. Starting with a set of related SQL views that can include existential subqueries in the conditions, the technique finds a database instance that can be used as a test-case for the target view. The proposal reduces the problem of generating the test-cases to a Constraint Satisfaction Problem using finite domain constraints. In particular...

Jacek Skowronek Distributed Optimization of Nested Queries