[teiid-dev] Connector supplied metadata

[John Doyle]

I think I've made my position on this feature clear in earlier threads.  This feature is to narrowly conceived.

Maybe the problem is that it has not been sufficiently explained, at least not in a public forum.  I don't have any problem with implementing a new vision over several versions, which I suspect is what you're doing, but what's the vision.  As far as I can tell from the public discussions and JIRAs, we are implementation a new API to be used in connector scope, and have an expectation that it will be grown into a full blown metadata API.  That's backwards in my opinion.  We should be defining the best API we can based upon the universe of potential environments/clients that we envision for Teiid.  We can then implement over successive versions in different components, right away in connectors if that's the priority.

I don't know enough to respond to the issue you raise.  Seems to me that it should have been resolved before this feature got on the roadmap and implemented.  

~jd


----- "Steven Hawkins" <shawkins at redhat.com> wrote:

> https://jira.jboss.org/jira/browse/TEIID-684 covers allowing
> connectors to supply metadata.  An initial check-in of this feature
> was added last night.  For those that are interested have a look at
> TestVDBLessExecution in the test-integration module.  
> 
> Through just a ConfigurationInfo.def file:
> 
> <VDB>
>     <VDBInfo>
>         <Property Name="Name" Value="VDBLess" />
>         <Property Name="Version" Value="4" />
>         <Property Name="UseConnectorMetadata" Value="true" />
>     </VDBInfo>
>     <Model>
>         <Property Name="Name" Value="SummitData" />
>         <ConnectorBindings>
>             <Connector Name="Text Connector" />
>         </ConnectorBindings>
>     </Model>
>     <ConnectorBindings>
>         <Connector Name="Text Connector" ComponentType="Text File
> Connector">
>             <Properties>
>                 <Property Name="Immutable">true</Property>
>                 <Property
> Name="DescriptorFile">src/test/resources/vdbless/TextDescriptor.txt</Property>
>             </Properties>
>         </Connector>
>     </ConnectorBindings>
> </VDB>
> 
> The text connector supplies the metadata for the SummitData model
> (through the TextDescriptor file).  I'll have the wiring added for the
> JDBC connector shortly along with additional metadata features, such
> as keys and procedures.
> 
> Note that the changes have heavily refactored the metadata module. 
> The intention is for 6.2 Designer to specifically fork the the 6.1
> version of the metadata code to provide their own implementation of
> the QueryMetadataInterface with their legacy usage of MetadataRecords.
>  This does not require any api level changes on their part or changes
> to the current preview integration mechanism.  There are currently no
> plans to incorporate this work into Designer as this is currently
> envisioned for ease of use of stand-alone Teiid.
> 
> An issue that is open for discussion is that the connector api now
> exposes the MetadataRecord objects as well as it the MetadataObject
> interfaces (Group, Element, etc).  A case could be made for expanding
> the MetadataObject interfaces to include getters and setters for all
> relevant fields on MetadataRecords (there are currently many fields
> that the user doesn't need to modify that are only used by index logic
> or are handled by the MetadataFactory).  We still however would need
> to have separate implementations of the interfaces since the Designer
> preview feature would still provide metadata through its QMI in the
> from of legacy MetadataRecords.  If we do expand the interfaces in
> this way, we would also probably want to add logic to ensure that no
> modifications can be performed when the records are supplied as
> RuntimeMetadata.
> 
> One warning that should be added is that since the metadata is
> non-persistent direct usage of uuid values in system tables should be
> discouraged.
> 
> Steve
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