I have been investigating using Micronaut Data JDBC as an augmentation for existing jdbi queries. Is it possible to do nested MappedEntity's and return the children?
Example is for a simple Warehouse Management System with a relation:
company
+- warehouse
+- inventory
What I'm wanting to be able to do is query up from the inventory table and get the parent of warehouse and grandparent of company. It is a one-to-many relationship with a company able to have multiple warehouses and a warehouse able to have multiple pieces of inventory.
My Entities look like
The example project I've been playing with is at wms-api
@JdbcRepository
interface CompanyRepository : PageableRepository<Company, UUID>
@MappedEntity
data class Company(
@field:Id
@field:GeneratedValue
var id: UUID? = null,
@field:GeneratedValue
var timeCreated: OffsetDateTime? = null,
@field:GeneratedValue
var timeUpdated: OffsetDateTime? = null,
var name: String
)
@JdbcRepository
interface WarehouseRepository : GenericRepository<Warehouse, UUID> { // used GenericRepository to allow the mapping of Company
@Join(value = "company")
fun findById(id: UUID): Warehouse?
@Join(value = "company")
fun findByCompany(company: Company, pageable: Pageable): Slice<Warehouse>
@Join(value = "company")
fun findAllByCompany(company: Company, pageable: Pageable): Slice<Warehouse>
@Join(value = "company")
fun existsByLocationAndCompany(location: String, company: Company): Boolean
fun save(warehouse: Warehouse): Warehouse
fun update(warehouse: Warehouse): Warehouse
}
@MappedEntity
data class Warehouse(
@field:Id @field:GeneratedValue
var id: UUID? = null,
@field:GeneratedValue
var timeCreated: OffsetDateTime? = null,
@field:GeneratedValue
var timeUpdated: OffsetDateTime? = null,
var location: String,
@field:Relation(value = MANY_TO_ONE)
var company: Company
)
@JdbcRepository
interface InventoryRepository : GenericRepository<Inventory, UUID> {
fun save(inventory: Inventory): Inventory
@Join(value = "warehouse")
// FIXME need some way to tell repo to also pull company which is attached to warehouse
fun findById(id: UUID): Inventory?
}
@MappedEntity
data class Inventory(
@field:Id
@field:GeneratedValue
var id: UUID? = null,
@field:GeneratedValue
var timeCreated: OffsetDateTime? = null,
@field:GeneratedValue
var timeUpdated: OffsetDateTime? = null,
var manufacturer: String,
var barcode: String,
var name: String,
@field:Relation(value = MANY_TO_ONE) // FIXME the problem is caused by this.
var warehouse: Warehouse,
)
Relevant part of the stacktrace
Caused by: io.micronaut.core.reflect.exception.InstantiationException: Null argument specified for [company]. If this argument is allowed to be null annotate it with @Nullable
at io.micronaut.core.beans.AbstractBeanIntrospection.instantiate(AbstractBeanIntrospection.java:121)
at io.micronaut.core.beans.BeanIntrospection.instantiate(BeanIntrospection.java:81)
at io.micronaut.data.runtime.mapper.sql.SqlResultEntityTypeMapper.readEntity(SqlResultEntityTypeMapper.java:345)
I would like to not have to make the Warehouse.company property optional if possible.
In the linked project there is a docker-compose.yml under support that can be used to fire up Postgres and then run the test suite, and the problem should pop up as a failure.
Thanks!