STORM: a statistical object representation model
SSDBM V Proceedings of the fifth international conference on Statistical and scientific database management
A universal-scheme approach to statistical databases containing homogeneous summary tables
ACM Transactions on Database Systems (TODS)
Implementing data cubes efficiently
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
An overview of data warehousing and OLAP technology
ACM SIGMOD Record
Proceedings of the 2nd ACM international workshop on Data warehousing and OLAP
Data Cube: A Relational Aggregation Operator Generalizing Group-By, Cross-Tab, and Sub-Total
ICDE '96 Proceedings of the Twelfth International Conference on Data Engineering
What can Hierarchies do for Data Warehouses?
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Answering Queries with Aggregation Using Views
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Summarizability in OLAP and Statistical Data Bases
SSDBM '97 Proceedings of the Ninth International Conference on Scientific and Statistical Database Management
Querying Multidimensional Databases
DBLP-6 Proceedings of the 6th International Workshop on Database Programming Languages
Maintaining Data Cubes under Dimension Updates
ICDE '99 Proceedings of the 15th International Conference on Data Engineering
Constraints on null values in relational databases
VLDB '81 Proceedings of the seventh international conference on Very Large Data Bases - Volume 7
A Decathlon in Multidimensional Modeling: Open Issues and Some Solutions
DaWaK 2000 Proceedings of the 4th International Conference on Data Warehousing and Knowledge Discovery
Hetero-homogeneous hierarchies in data warehouses
APCCM '10 Proceedings of the Seventh Asia-Pacific Conference on Conceptual Modelling - Volume 110
Data warehouse design on the basis of Hierarchical Degenerate Snowflake (HDS)
International Journal of Business Intelligence and Data Mining
Repairing dimension hierarchies under inconsistent reclassification
ER'11 Proceedings of the 30th international conference on Advances in conceptual modeling: recent developments and new directions
Extending visual OLAP for handling irregular dimensional hierarchies
DaWaK'06 Proceedings of the 8th international conference on Data Warehousing and Knowledge Discovery
Modeling data warehouse schema evolution over extended hierarchy semantics
Journal on Data Semantics XIII
Repair-oriented relational schemas for multidimensional databases
Proceedings of the 15th International Conference on Extending Database Technology
Repairing inconsistent dimensions in data warehouses
Data & Knowledge Engineering
Using domain ontologies as semantic dimensions in data warehouses
ER'12 Proceedings of the 31st international conference on Conceptual Modeling
A multidimensional data model with subcategories for flexibly capturing summarizability
Proceedings of the 25th International Conference on Scientific and Statistical Database Management
Extended dimensions for cleaning and querying inconsistent data warehouses
Proceedings of the sixteenth international workshop on Data warehousing and OLAP
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In OLAP applications, data are modeled as points in a multidimensional space. Dimensions themselves have structure, described by a schema and an instance; the schema is basically a directed acyclic graph of granularity levels, and the instance consists of a set of elements for each level and mappings between these elements, usually called rollup functions. Current dimension models restrict dimensions in various ways; for example, rollup functions are restricted to be total. We relax these restrictions, yielding what we call heterogeneous schemas, which describe more naturally and cleanly many practical situations. In the context of heterogeneous schemas, the notion of summarizability becomes more complex. An aggregate view defined at some granularity level is summarizable from a set of precomputed views defined at other levels if the rollup functions can be used to compute the first view from the set of views. In order to study summarizability in heterogeneous schemas, we introduce a class of constraints on dimension instances that enrich the semantics of dimension hierarchies, and we show how to use the constraints to characterize and test for summarizability.