Formal languages
Journal of Computer and System Sciences - 3rd Annual Conference on Structure in Complexity Theory, June 14–17, 1988
Pattern matching by Rs-operations: towards a unified approach to querying sequenced data
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The closure of Monadic NP (extended abstract)
STOC '98 Proceedings of the thirtieth annual ACM symposium on Theory of computing
Sequences, datalog, transducers
Journal of Computer and System Sciences - Fourteenth ACM SIGACT-SIGMOD-SIGART symposium on principles of database systems
Algebras for querying text regions: expressive power and optimization
Journal of Computer and System Sciences - Fourteenth ACM SIGACT-SIGMOD-SIGART symposium on principles of database systems
Finite queries do not have effective syntax
Information and Computation
A technique for proving decidability of containment and equivalence of linear constraint queries
Journal of Computer and System Sciences
Reasoning about strings in databases
Journal of Computer and System Sciences
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Relational queries over interpreted structures
Journal of the ACM (JACM)
SIAM Journal on Computing
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Querying String Databases with Transducers
DBLP-6 Proceedings of the 6th International Workshop on Database Programming Languages
First-Order Logic vs. Fixed-Point Logic in Finite Set Theory
LICS '99 Proceedings of the 14th Annual IEEE Symposium on Logic in Computer Science
LICS '00 Proceedings of the 15th Annual IEEE Symposium on Logic in Computer Science
SPIRE '99 Proceedings of the String Processing and Information Retrieval Symposium & International Workshop on Groupware
Safety, translation and evaluation of alignment calculus
ADBIS'97 Proceedings of the First East-European conference on Advances in Databases and Information systems
Applications of Alfred Tarski's Ideas in Database Theory
CSL '01 Proceedings of the 15th International Workshop on Computer Science Logic
Unification with Sequence Variables and Flexible Arity Symbols and Its Extension with Pattern-Terms
AISC '02/Calculemus '02 Proceedings of the Joint International Conferences on Artificial Intelligence, Automated Reasoning, and Symbolic Computation
Design and implementation of a string database query language
Information Systems - Special issue: Data management in bioinformatics
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We study relational calculi with support for string operations. While SQL restricts the ability to mix string pattern-matching and relational operations, prior proposals for embedding SQL in a compositional calculus were based on adding the operation of concatenation to first-order logic. These latter proposals yield compositional query languages extending SQL, but are unfortunately computationally complete. The unbounded expressive power in turn implies strong limits on the ability to perform optimization and static analysis of properties such as query safety in these languages.In contrast, we look at compositional extensions of relational calculus that have nice expressiveness, decidability, and safety properties, while capturing string-matching queries used in SQL. We start with an extension based on the string ordering and LIKE predicates. This extension shares some of the attractive properties of relational calculus (e.g. effective syntax for safe queries, low data complexity), but lacks the full power of regular-expression pattern-matching. When we extend this basic model to include string length comparison, we get a natural string language with great expressiveness, but one which includes queries with high (albeit bounded) data complexity. We thus explore the space between these two languages. We consider two intermediate languages: the first extends our base language with functions that trim/add leading characters, and the other extends it by adding the full power of regular-expression pattern-matching. We show that both these extensions inherit many of the attractive properties of the basic model: they both have corresponding algebras expressing safe queries, and low complexity of query evaluation.