Question

I have: ‘image’ 1:Many ‘imageToTag’ Many:1 ‘tag’

I want to issue a query that will return all images that have at least tags [a, b, c]. It’s not clear to me how one can model this in JPQL. I could build the query string dynamically but that’s bad for performance and security reasons. Any ideas?

Answer 1

In PSEUDO CODE:

SELECT * FROM IMAGES    INNER JOIN IMAGETAGS A     ON IMAGE.ID = A.IMAGEID AND A.TAGID = 'A'   INNER JOIN IMAGETAGS B     ON IMAGE.ID = B.IMAGEID AND B.TAGID = 'B'   INNER JOIN IMAGETAGS C     ON IMAGE.ID = C.IMAGEID AND C.TAGID = 'C' 

Just guessing, but the equivalent in JPQL would be

Select img from Image img   JOIN img.tag ta   JOIN img.tag tb   JOIN img.tag tc    WHERE ta.description = 'A' and tb.description = 'B' and tc.description = 'C'