Book Image

Applying and Extending Oracle Spatial

By : Siva Ravada, Simon Greener
Book Image

Applying and Extending Oracle Spatial

By: Siva Ravada, Simon Greener

Overview of this book

Spatial applications should be developed in the same way that users develop other database applications: by starting with an integrated data model in which the SDO_GEOMETRY objects are just another attribute describing entities and by using as many of the database features as possible for managing the data. If a task can be done using a database feature like replication, then it should be done using the standard replication technology instead of inventing a new procedure for replicating spatial data. Sometimes solving a business problem using a PL/SQL function can be more powerful, accessible, and easier to use than trying to use external software. Because Oracle Spatial's offerings are standards compliant, this book shows you how Oracle Spatial technology can be used to build cross-vendor database solutions. Applying and Extending Oracle Spatial shows you the clever things that can be done not just with Oracle Spatial on its own, but in combination with other database technologies. This is a great resource book that will convince you to purchase other Oracle technology books on non-spatial specialist technologies because you will finally see that "spatial is not special: it is a small, fun, and clever part of a much larger whole".
Table of Contents (20 chapters)
Applying and Extending Oracle Spatial
About the Authors
About the Reviewers
Table Comparing Simple Feature Access/SQL and SQL/MM–Spatial

Parallel queries and partitioning

One of the benefits of partitioning is the ability to parallelize spatial queries. If the query window spans multiple partitions (as is likely to happen with DATE based partitioning), then each partition can be queried in parallel. But the default behavior of partitioned spatial queries is not suitable for queries that span a large number of partitions on systems that have a large number of processors available for the queries. When a spatial query is issued against a partitioned spatial table and no partition key is used in the Where clause, then the spatial internally rewrites the query so that only those partitions that can potentially interact with the given window geometry are used. This is done by doing the spatial pruning query internally to find the list of partitions that can potentially interact with the window geometry, and this list of partitions is added to the Where clause. So, the user query is transformed to a query with additional predicates...