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9.10. Metadata Repositories

Traditionally the metadata for a Virtual Database is built by Teiid Designer and supplied to Teiid engine through a VDB archive file. This VDB file contains .INDEX metadata files. By default they are loaded by a MetadataRepository with the name INDEX. Other built-in metadata repositories include the following:
NATIVE
This is only applicable on source models (and is also the default), when used the metadata for the model is retrieved from the source database itself. 
<vdb name="{vdb-name}" version="1">
    <model name="{model-name}" type="PHYSICAL">
        <source name="AccountsDB" translator-name="oracle" connection-jndi-name="java:/oracleDS"/>
        <metadata type="NATIVE"></metadata>
    </model>
</vdb>
DDL 
<vdb name="{vdb-name}" version="1">
    <model name="{model-name}" type="PHYSICAL">
        <source name="AccountsDB" translator-name="oracle" connection-jndi-name="java:/oracleDS"/>
        <metadata type="DDL">
          **DDL Here**
        </metadata>
    </model>
</vdb>
This is applicable to both source and view models. See DDL Metadata for more information on how to use this feature.
DDL-FILE 
<vdb name="{vdb-name}" version="1">
    <model name="{model-name}" type="PHYSICAL">
        <source name="AccountsDB" translator-name="oracle" connection-jndi-name="java:/oracleDS"/>
        <metadata type="DDL-FILE">/accounts.ddl</metadata>
    </model>
</vdb>
DDL is applicable to both source and view models in zip VDB deployments. See DDL Metadata for more information on how to use this feature.
Chaining Repositories
When defining the metadata type for a model, multiple metadata elements can be used. All the repository instances defined are consulted in the order configured to gather the metadata for the given model. 
<vdb name="{vdb-name}" version="1">
    <model name="{model-name}" type="PHYSICAL">
        <source name="AccountsDB" translator-name="oracle" connection-jndi-name="java:/oracleDS"/>
        <metadata type="NATIVE"/>
        <metadata type="DDL">
          **DDL Here**
        </metadata>
    </model>
</vdb>
For the above model, NATIVE importer is first used, then DDL importer used to add additional metadata to NATIVE imported metadata.