Relative information capacity of simple relational database schemata
SIAM Journal on Computing
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Sets and negation in a logic data base language (LDL1)
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
A translation language complete for database update and specification
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
IFO: a formal semantic database model
ACM Transactions on Database Systems (TODS)
Semantic database modeling: survey, applications, and research issues
ACM Computing Surveys (CSUR)
Negation as failure using tight derivations for general logic programs
Foundations of deductive databases and logic programming
Possibilities and limitations of using flat operators in nested algebra expressions
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Procedural and declarative database update languages
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The functional data model and the data languages DAPLEX
ACM Transactions on Database Systems (TODS)
Database description with SDM: a semantic database model
ACM Transactions on Database Systems (TODS)
Journal of the ACM (JACM)
Universality of data retrieval languages
POPL '79 Proceedings of the 6th ACM SIGACT-SIGPLAN symposium on Principles of programming languages
A new approach to database logic
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
Remarks on the algebra of non first normal form relations
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Horn clauses and the fixpoint query hierarchy
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Extended Algebra and Calculus for ~1NF Relational Databases
Extended Algebra and Calculus for ~1NF Relational Databases
On accessing object-oriented databases: expressive power, complexity, and restrictions
SIGMOD '89 Proceedings of the 1989 ACM SIGMOD international conference on Management of data
Untyped sets, invention, and computable queries
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
ACM SIGACT News
On the power of rule-based languages with sets
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The expressiveness of a family of finite set languages
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Tractable query languages for complex object databases
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Converting nested algebra expressions into flat algebra expressions
ACM Transactions on Database Systems (TODS)
Towards tractable algebras for bags
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Database method schemas and object creation
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Hi-index | 0.00 |
The set-height of a complex object type is defined to be its level of nesting of the set construct. In a query of the complex object calculus which maps a database D to an output type T, an intermediate type is a type which is used by some variable of the query, but which is not present in D or T. For each k, i ≥ 0 we define CALCk,i to be the family of calculus queries mapping from and to types with set-height ≤ k and using intermediate types with set-height ≤ i In particular, CALC0,0 is the relational calculus, and CALC0,1 is equivalent to the family of second-order (relational) queriesSeveral results concerning these families of languages are obtained. A primary focus is on the families CALC0,i, which map relations to relations Upper bounds on the complexity of these families are provided, and it is shown that CALC0,3 has at least the complexity of exponential space. The CALC0,i hierarchy does not collapse, because for each i, CALC0,i is strictly less expressive than CALC0,i+2. The union ∪0≤iCALC0,i is strictly less expressive than the family of 'computable' database queries.The expressive power of queries from the complex object calculus interpreted using a semantics based on the use of arbitrarily large finite numbers of invented values is studied. Under this semantics, the expressive power of the relational calculus is not increased, and the CALC0,i hierarchy collapses at CALC0,1. We also consider queries which use a bounded number of invented values.