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Posted to user@cayenne.apache.org by Hugi Thordarson <hu...@karlmenn.is> on 2016/03/25 17:45:04 UTC

Expression for checking if a to-many relationship contains an object

Hi all!

Subject says it all, really. How do I write an Expression to fetch all records where a to-many relationship contains an object.

For example, let’s say a “Person” entity has a to-many relationship to an “Employment" entity, which is then linked to a “Company” entity. And I want to fetch all “Person” records that are linked to a certain company record.

Cheers,
- hugi

Re: Expression for checking if a to-many relationship contains an object

Posted by Hugi Thordarson <hu...@karlmenn.is>.
> On 25. mar. 2016, at 17:46, Andrus Adamchik <an...@objectstyle.org> wrote:
> 
> 
>> On Mar 25, 2016, at 7:45 PM, Hugi Thordarson <hu...@karlmenn.is> wrote:
>> 
>> Hi all!
>> 
>> Subject says it all, really. How do I write an Expression to fetch all records where a to-many relationship contains an object.
>> 
>> For example, let’s say a “Person” entity has a to-many relationship to an “Employment" entity, which is then linked to a “Company” entity. And I want to fetch all “Person” records that are linked to a certain company record.\
> 
> Something like "employments.company = $company" should work. This results in simple joins across to-many, and should give you what you need.

Of course. Works like a charm, thanks!

- hugi

Re: Expression for checking if a to-many relationship contains an object

Posted by Andrus Adamchik <an...@objectstyle.org>.
> On Mar 25, 2016, at 7:45 PM, Hugi Thordarson <hu...@karlmenn.is> wrote:
> 
> Hi all!
> 
> Subject says it all, really. How do I write an Expression to fetch all records where a to-many relationship contains an object.
> 
> For example, let’s say a “Person” entity has a to-many relationship to an “Employment" entity, which is then linked to a “Company” entity. And I want to fetch all “Person” records that are linked to a certain company record.\

Something like "employments.company = $company" should work. This results in simple joins across to-many, and should give you what you need.

Andrus