Thank you Nikita, that helps me.
In EOF we use them in memory as well as for fetching from the database.
In Cayenne it seems that once I call exists() then the expression cannot be
used for filtering in memory.
For example:
Expression expr = exp("paintings.name like 'S%'").exists();
List<Artist> someArtists = ObjectSelect
.query(Artist.class)
.where(expr)
.select(context);
The above matches 1 artist, e.g. “Vincent Van Gogh” who has a paintings
starting with the letter S, e.g. Starry Night and Sunflowers. But when I use
that same expression against a list of all the artists like this:
List<Artist> someArtists2 = expr.filterObjects(allArtists);
Then someArtists2 is empty.
However, if I rewrite the code as follows:
Expression expr = exp("paintings.name like 'S%'");
List<Artist> someArtists = ObjectSelect
.query(Artist.class)
.where(expr.exists())
.select(context);
// This matches 1 artist
List<Artist> someArtists2 = expr.filterObjects(allArtists);
Regards,
Ricardo Parada
> On Sep 27, 2025, at 12:26 PM, Nikita Timofeev <[email protected]>
> wrote:
>
> Hi Ricardo,
>
> Yeah, there's not much info on that since that's a new API. `exists()` is a
> terminal operator that converts the whole expression to an EXISTS query.
>
> So it would be something like this in your
> example: Artist.PAINTINGS.dot(Painting.NAME).like("painting%").exists()
>
>
> On Fri, Sep 26, 2025 at 8:31 PM Ricardo Parada <[email protected]>
> wrote:
>
>> Hi all,
>>
>> Another question I have is regarding EXISTS expressions. I’m not sure if
>> I’m using the API correctly, but I was thinking it would be something like
>> this. Using the entities from the Tutorial, let’s say I want to fetch the
>> Artist’s that have a painting starting with the letter ‘G’:
>>
>> Expression e = Artist.PAINTINGS.exists(Painting.NAME.like(“G%”));
>>
>> But I’m getting a syntax error.
>
>
>
> --
> Best regards,
> Nikita Timofeev
