Incorporating Hypothetical Views and Extended Recursion into SQL Database Systems
Gabriel Aranda, Susana Nieva, Fernando Sáenz-Pérez, Jaime Sánchez-Hernández · EPiC series in computing · 2018
Current database systems supporting recursive SQL impose restrictions on queries such as linearity, and do not implement mutual recursion. In a previous work we presented the language and prototype R-SQL to overcome those drawbacks. Now we introduce a formalization and an implementation of the database system HR-SQL that, in addition to extended recursion, incorporates hypothetical reasoning in a novel way which cannot be found in any other SQL system, allowing both positive and negative assumptions. The formalization extends the fixpoint semantics of R-SQL. The implementation improves the eciency of the previous prototype and is integrated in a commercial DBMS.