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

Geometry type implementation matrix

From what we have learned so far, a table/column implementation matrix can be produced that will allow us to implement all possible variations of the SQL/MM Spatial standard. In the following diagram, the matrix is implemented only for the ST_POINT subtype. However, included with this book are a set of SQL files that provide an implementation of the standard's ST_* geometry types. No Primary Key attribute and constraint text is included for brevity's sake in any of the implementations shown in the following diagram:

Because some Oracle geometry subtypes (CircularString) can only be identified by functions that cannot be used by CHECK constraints (such as Get_WKT), a trigger must be constructed to implement the constraint:

Create Or Replace Trigger st_road_circularstring_biu 
Before Insert or update on ST_ROAD 
Referencing old As old new As new 
For Each Row
  If (:new.GEOM IS NULL) Then
  End If;
  If (:new.GEOM IS NOT NULL And