Finite automata and unary languages
Theoretical Computer Science
Rational relations with bounded delay
STACS 91 Proceedings of the 8th annual symposium on Theoretical aspects of computer science
Finding Regular Simple Paths in Graph Databases
SIAM Journal on Computing
Algorithms on strings, trees, and sequences: computer science and computational biology
Algorithms on strings, trees, and sequences: computer science and computational biology
Query containment for conjunctive queries with regular expressions
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
GraphLog: a visual formalism for real life recursion
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
On the complexity of integer programming
Journal of the ACM (JACM)
Data on the Web: from relations to semistructured data and XML
Data on the Web: from relations to semistructured data and XML
Flexible queries over semistructured data
PODS '01 Proceedings of the twentieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Formal-Language-Constrained Path Problems
SIAM Journal on Computing
Counter machines and verification Problems
Theoretical Computer Science
Index Structures for Path Expressions
ICDT '99 Proceedings of the 7th International Conference on Database Theory
Optimization Properties for Classes of Conjunctive Regular Path Queries
DBPL '01 Revised Papers from the 8th International Workshop on Database Programming Languages
Ρ-Queries: enabling querying for semantic associations on the semantic web
WWW '03 Proceedings of the 12th international conference on World Wide Web
LICS '00 Proceedings of the 15th Annual IEEE Symposium on Logic in Computer Science
Structure of complexity in the weak monadic second-order theories of the natural numbers
STOC '74 Proceedings of the sixth annual ACM symposium on Theory of computing
Definable relations and first-order query languages over strings
Journal of the ACM (JACM)
SPARQ2L: towards support for subgraph extraction queries in rdf databases
Proceedings of the 16th international conference on World Wide Web
Lower bounds for natural proof systems
SFCS '77 Proceedings of the 18th Annual Symposium on Foundations of Computer Science
SPARQLeR: Extended Sparql for Semantic Association Discovery
ESWC '07 Proceedings of the 4th European conference on The Semantic Web: Research and Applications
Database and information-retrieval methods for knowledge discovery
Communications of the ACM - A Direct Path to Dependable Software
Extending SPARQL with regular expression patterns (for querying RDF)
Web Semantics: Science, Services and Agents on the World Wide Web
Unary finite automata vs. arithmetic progressions
Information Processing Letters
Bad news on decision problems for patterns
Information and Computation
On relations defined by generalized finite automata
IBM Journal of Research and Development
Using annotations from controlled vocabularies to find meaningful associations
DILS'07 Proceedings of the 4th international conference on Data integration in the life sciences
Expressive languages for path queries over graph-structured data
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
nSPARQL: A navigational language for RDF
Web Semantics: Science, Services and Agents on the World Wide Web
On the complexity of equational horn clauses
CADE' 20 Proceedings of the 20th international conference on Automated Deduction
Semantic acyclicity on graph databases
Proceedings of the 32nd symposium on Principles of database systems
Proceedings of the 32nd symposium on Principles of database systems
Trial for RDF: adapting graph query languages for RDF data
Proceedings of the 32nd symposium on Principles of database systems
Hi-index | 0.00 |
For many problems arising in the setting of graph querying (such as finding semantic associations in RDF graphs, exact and approximate pattern matching, sequence alignment, etc.), the power of standard languages such as the widely studied conjunctive regular path queries (CRPQs) is insufficient in at least two ways. First, they cannot output paths and second, more crucially, they cannot express relationships among paths. We thus propose a class of extended CRPQs, called ECRPQs, which add regular relations on tuples of paths, and allow path variables in the heads of queries. We provide several examples of their usefulness in querying graph structured data, and study their properties. We analyze query evaluation and representation of tuples of paths in the output by means of automata. We present a detailed analysis of data and combined complexity of queries, and consider restrictions that lower the complexity of ECRPQs to that of relational conjunctive queries. We study the containment problem, and look at further extensions with first-order features, and with nonregular relations that add arithmetic constraints on the lengths of paths and numbers of occurrences of labels.