Query projection not possible for embedded IDs

[esocode]

Task List

• [x] Steps to reproduce provided
• [x] Stacktrace (if present) provided
• [ ] Example that reproduces the problem uploaded to Github
• [x] Full description of the issue provided (see below)

I have a child entity with an embedded ID field called id, containing two integer fields: parentId, number. I need to find the maximum number value for a certain parent ID. So I defined the following query method with a max projection on the ID's number:

int findMaxIdNumberByIdParentId(int parentId);

When compiling this only yields an error message:

Unable to implement Repository method: ChildRepository.findMaxIdNumberByIdParentId(int parentId). Cannot project on non-existent property idNumber

The only workaround at the moment is to build a native query with EntityManager as defining a method with an explicit query also doesn't work because of another bug (reported in #653).

Steps to Reproduce

1. Define entity with embedded ID
2. Define repository query method with projection on ID field
3. compile => error

Expected Behaviour

Projections on embedded ID should work

Actual Behaviour

Compile error

Environment Information

• Operating System: Windows 10
• Micronaut Version: 2.0.0 (data 1.1.1)
• JDK Version: 8

[jameskleeh]

Does int findMaxNumberByParentId(int parentId); work?

[esocode]

No. Sorry, I forgot to mention that one. It was actually my first try but it caused an error too. I have to check this, but as far as I remember it produced a hibernate runtime error that the field could not be found. I'll try tomorrow and provide the exact error message.

[esocode]

My first try was actually findMaxNumberByIdParentId(int) which yields the following exception at runtime:

java.util.concurrent.CompletionException: java.lang.IllegalArgumentException: org.hibernate.QueryException: could not resolve property: number of: sample.pkg.Child [SELECT MAX(child_.number) FROM sample.pkg.Child AS child_ WHERE (child_.id.parentId = :p1)]

Your variant findMaxNumbeByParentId fails on both attributes:

java.util.concurrent.CompletionException: java.lang.IllegalArgumentException: org.hibernate.QueryException: could not resolve property: number of: sample.pkg.Child [SELECT MAX(child_.number) FROM sample.pkg.Child AS child_ WHERE (childId_.parentId.parentId = :p1)]

The WHERE clause in the first variant is correctly mapped on the embedded ID (child_.id.parentId). I use this in several queries which work without problems. So I think that the bug is that the projection MaxIdNumber is not mapped in the same way as the criteria. Would that be mapped to child_.id.number the query should work.

[esocode]

I just noticed the same problem for deletes. The projection deleteByIdParentId(int) won't compile and the variant deleteByParentId(int)throws an exception at runtime. Is this the same problem or justifies it a separate issue? Or isn't it supported?

[graemerocher]

probably the same problem

[charlie-harvey]

Would this be the same problem if I was trying to project on a joined table/column?

@Entity
data class Product(
    @field:Id
    @field:GeneratedValue
    var id: Long?,
    var name: String,
    @field:Relation(value = Relation.Kind.MANY_TO_ONE)
    @field:MappedProperty("manufacturerId")
    var manufacturer: Manufacturer?
)

@Repository
@JdbcRepository(dialect = Dialect.MYSQL)
interface ProductRepository :CrudRepository<Product, Long> {
    fun findByManufacturerId(long manufacturerId): Product?
}

[Goldmensch]

Any update on this? I have the same problem with data jdbc.

[radovanradic]

This seems to be fixed in Micronaut version 3.9.0 when similar issue #1898 was fixed.