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

Streams based replication

Oracle provides two basic technologies for general replication between two or more Oracle databases, namely, advanced replication and streams based replication. The streams based replication provides a more efficient solution than the one based on advanced replication. Rather than synchronously capturing changes in the materialized view logs, which adds overhead to the transaction, streams mine the redo logs created by the updates to the database and create change logs to send to the target database system. This architecture also allows the change to be replicated to more than one system much more quickly. The advanced replication also has some restrictions with SDO_GEOMETRY types that are harder to work around.

In this section, we will describe the streams based replication for the tables with SDO_GEOMETRY columns. Note that even the native streams based replication has restrictions for the tables with SDO_GEOMETRY columns. But procedures can be easily implemented...