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

Packaging or encapsulation functions

Many functions (some dependent on others) have been created, but over time, an even larger library of (possibly interdependent) functions may come into existence, which may increase fragility unless dependencies are managed, and the compilation of each function occurs in the right order. In addition, it may be necessary to call a specific function in different ways even though they all implement exactly the same functionality.

Oracle offers us a number of ways to handle these situations.

Calling the same processing in different ways

The ST_Dimension function must be called with an SDO_GEOMETRY parameter. However, it may be more efficient to call the function with an SDO_GEOMETRY object's SDO_GTYPE numeric attribute; after all, the ST_Dimension function's processing is based entirely on this attribute. The current ST_Dimension function cannot be called with a non-SDO_GEOMETRY parameter value:

With testGeom As (