External materialized views cache their data in an external database system. External materialized views give the administrator full control over the loading and refresh strategies.

Since the actual physical cache for materialized views is maintained external to the Teiid system, there is no predefined policy for clearing and managing the cache. These policies should be defined and enforced by administrators of the Teiid system based on their needs.

Typical Usage Steps

• Create materialized views and corresponding physical materialized target tables in Designer. This can be done through setting the materialized and target table manually, or by selecting the desired views, right clicking, then selecting Modeling->"Create Materialized Views"

• Generate the DDL for your physical model materialization target tables. This can be done by selecting the model, right clicking, then choosing Export->"Metadata Modeling"->"Data Definition Language (DDL) File". This script can be used to create the desired schema for your materialization target on whatever source you choose.

• Determine a load and refresh strategy. With the schema created the most simplistic approach is to just load the data. The load can even be done through Teiid with

insert into target\_table select * from matview option nocache

That however may be too simplistic because your index creation may be more performant if deferred until after the table has been created. Also full snapshot refreshes are best done to a staging table then swapping it for the existing physical table to ensure that the refresh does not impact user queries and to ensure that the table is valid prior to use.