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

Processing a collection of geometries


The preceding examples focused on the processing of one, then two geometries. In this section we will look at the processing of a collection (more than two) of SDO_GEOMETRY objects. The presentation of this type of processing will take place around solving a real world problem; creating land parcel polygons from their boundaries described by linestrings. This will require the following types of processing of collections of geometries:

  • Forming nodes between a collection of linestrings

  • Forming polygons from a collection of noded linestrings

Types of collections

Being inside the Oracle database, we have a limited number of methods or data types that can be used to represent a collection of geometry objects, which can be passed to our Java code for processing. These methods or collection types draw from SQL, PL/SQL and OGC SFA's geometry type hierarchy. They include:

  • A REF CURSOR/result set (Java type Java.sql.ResultSet):

    TYPE refcur_t IS REF CURSOR; -- or SYS_REFCURSOR...