A system for semantic query optimization
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Logic-based approach to semantic query optimization
ACM Transactions on Database Systems (TODS)
Formal semantics of SQL queries
ACM Transactions on Database Systems (TODS)
Optimization of real conjunctive queries
PODS '93 Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Containment of conjunctive queries: beyond relations as sets
ACM Transactions on Database Systems (TODS)
An overview of data warehousing and OLAP technology
ACM SIGMOD Record
On optimizing an SQL-like nested query
ACM Transactions on Database Systems (TODS)
An extended relational algebra with control over duplicate elimination
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Semantic Query Optimization for Tree and Chain Queries
IEEE Transactions on Knowledge and Data Engineering
Performing Group-By before Join
Proceedings of the Tenth International Conference on Data Engineering
Implementation of Two Semantic Query Optimization Techniques in DB2 Universal Database
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
The Magic of Duplicates and Aggregates
VLDB '90 Proceedings of the 16th International Conference on Very Large Data Bases
Algebraic Properties of Bag Data Types
VLDB '91 Proceedings of the 17th International Conference on Very Large Data Bases
Including Group-By in Query Optimization
VLDB '94 Proceedings of the 20th International Conference on Very Large Data Bases
Aggregate-Query Processing in Data Warehousing Environments
VLDB '95 Proceedings of the 21th International Conference on Very Large Data Bases
Eager Aggregation and Lazy Aggregation
VLDB '95 Proceedings of the 21th International Conference on Very Large Data Bases
Processing star queries on hierarchically-clustered fact tables
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
Exploiting hierarchical clustering in evaluating multidimensional aggregation queries
DOLAP '03 Proceedings of the 6th ACM international workshop on Data warehousing and OLAP
Supporting ad-hoc ranking aggregates
Proceedings of the 2006 ACM SIGMOD international conference on Management of data
Hierarchical clustering for OLAP: the CUBE File approach
The VLDB Journal — The International Journal on Very Large Data Bases
Optimized union of non-disjoint distributed data sets
Proceedings of the 12th International Conference on Extending Database Technology: Advances in Database Technology
Integrating Star and Snowflake Schemas in Data Warehouses
International Journal of Data Warehousing and Mining
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One of the recently proposed techniques for the efficient evaluation of OLAP aggregate queries is the usage of clustering access methods. These methods store the fact table of a data warehouse clustered according to the dimension hierarchies using special attributes called hierarchical surrogate keys. In the presence of these access methods new processing and optimization techniques have been recently proposed. One important such optimization technique, called Hierarchical Pre-Grouping, uses the hierarchical surrogate keys in order to aggregate the fact table tuples as early as possible and to avoid redundant joins. In this paper, we study the Pre-Grouping transformation, attempting to generalize its applicability and identify its relationship to other similar transformations. Our results include a general algebraic definition of the Pre-Grouping transformation along with the formal definition of sufficient conditions for applying the transformation. Using a provided theorem we show that Pre-Grouping can be applied in the presence of functional and inclusion dependencies without the explicit usage of hierarchical surrogate keys. An additional result of our study is the definition of the Surrogate-Join transformation that can modify a join condition using a number of dependencies. To our knowledge, Surrogate-Join does not belong to any of the Semantic Query Transformation types discussed in the past.