[OASIS Issue Tracker] Commented: (ODATA-36) Make $expand implicit if navigation properties are mentioned in $select or $aggregate

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    [ http://tools.oasis-open.org/issues/browse/ODATA-36?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=31307#action_31307 ] 

Michael Pizzo commented on ODATA-36:
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Although select and expand (and filter, orderby, etc.) may be taken into account when translating into SQL, separating the concerns is important.

$expand increases the set of rows returned. Servers must honor the $expand or fail the request. $expand must be evaluated when generating the results (for example, in generating the query).

$select is a hint to the servers to reduce the set of fields returned. $select can be applied after the results are generated, even by the formatter, as an optimization to reduce the data returned. While servers are encouraged to support $select, it is valid for them to return additional information not specified in the $select, including ignoring the $select and returning the entire record.

These two have different semantics that may be applied at different times and should not be mixed.

Also, we are looking at adding options to the $expand clause to do things like filter or sort the expanded entities. I would not want to add this complexity specific to navigation properties to $select, nor would I want to have $expand used in one case and not in other cases.

> Make $expand implicit if navigation properties are mentioned in $select or $aggregate
> -------------------------------------------------------------------------------------
>
>                 Key: ODATA-36
>                 URL: http://tools.oasis-open.org/issues/browse/ODATA-36
>             Project: OASIS Open Data Protocol (OData) TC
>          Issue Type: Improvement
>          Components: OData Protocol v1.0, OData URL Conventions v1.0
>    Affects Versions: WD01
>         Environment: [Proposed]
>            Reporter: Martin Zurmuehl
>            Priority: Minor
>             Fix For: WD01
>
>
> Currently clients need to repeat themselves when projecting on expanded entities:
> GET http://services.odata.org/OData/OData.svc/Products?$select=*,Category/Name&$expand=Category
> This could be reduced to 
> GET http://services.odata.org/OData/OData.svc/Products?$select=*,Category/Name
> because the client explicitly requests Category/Name, and the server can only satisfy that if it expands the Category.

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