Extended algebra and calculus for nested relational databases
ACM Transactions on Database Systems (TODS)
Language features for interoperability of databases with schematic discrepancies
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
SQL: 1999, formerly known as SQL3
ACM SIGMOD Record
Extending the database relational model to capture more meaning
ACM Transactions on Database Systems (TODS)
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
Complex Aggregation at Multiple Granularities
EDBT '98 Proceedings of the 6th International Conference on Extending Database Technology: Advances in Database Technology
Rethinking Database System Architecture: Towards a Self-Tuning RISC-Style Database System
VLDB '00 Proceedings of the 26th International Conference on Very Large Data Bases
Querying Multiple Features of Groups in Relational Databases
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Evaluation of Ad Hoc OLAP: In-Place Computation
SSDBM '99 Proceedings of the 11th International Conference on Scientific and Statistical Database Management
Integrated decision support for sustainable forest management in the United States: Fact or fiction?
Computers and Electronics in Agriculture
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In most forested environments, boreal forest in particular, monitoring and evaluation of management activities would be facilitated by storage of multiscale data sets spanning long time periods. For this study, such a data repository based on a generic spatio-temporal conceptual data model was created using XML. The data repository containing changes in data content for a 1000ha forest estate between 1871 and 1994 was used to evaluate the data retrieval capabilities of XQuery. The data retrieval operations consisted of pivoting, sequencing, and aggregation. Pivoting transforms the generic attribute storage used in the data model into a more compact column-wise format. Sequencing is used to return a temporal sequence of values, and for the traversal of the object hierarchy. Aggregation aggregates the values of a variable over a grouping variable. The combinations of the basic retrieval operations were also investigated as well as the effect of time and object hierarchy on the retrieval operations. The conceptual match between the generic spatio-temporal data model and the XML data model was apparent at the data retrieval operations. The key properties of XQuery for the implementation of the retrieval operations were extendability, support for nested structures, and data transformation functionality.