Book Image

Applying and Extending Oracle Spatial

Book Image

Applying and Extending Oracle Spatial

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
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Table Comparing Simple Feature Access/SQL and SQL/MM–Spatial
Index

Spatial indexing


Spatial indexing is one of the most important concepts in Oracle Spatial. Using the index can dramatically reduce the query cost for many operations. As Oracle uses an R-tree index, there are actually no maintenance operations required once the index is built. However, there are several important considerations while building the index to get the best possible performance for queries. In the following section, we describe some of the most commonly used parameters in the Create Index statement.

Layer GTYPE for point data

As we mentioned in Chapter 1, Defining a Data Model for Spatial Data Storage, the LAYER_GTYPE parameter can be used to enforce type consistency across all the rows in the table. For point data, this parameter can also be used to improve the performance for spatial index-based queries against these tables. When an operator like SDO_RELATE is evaluated, the R-tree index is used to do the primary filtering. In some cases, the index nodes can be used to perform...