Spring Data JPA does findAll retrieve data from associated table in a onetoone mapping? - spring-data-jpa

Question

I am using Spring Data JPA. I have 2 tables as follows:
Investment and Investment_Type. There is a one to one relationship between Investment and Investment_Type.
My Investment class is as follows:
#Entity
public class Investment {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private int investmentId;
#NotNull(message = "Cannot be empty")
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "investment_type_id")
private InvestmentType investmentType;
#NotNull(message = "Cannot be empty")
private String investmentNumber;
//getter and setter methods
}
My InvestmentType class is as follows:
#Entity
public class InvestmentType {
#Id #GeneratedValue(strategy=GenerationType.AUTO)
private Integer investmentTypeId;
private String investmentTypeName;
//getter and setter methods
}
My InvestmentRepository is as follows:
public interface InvestmentRepository extends JpaRepository <Investment, Integer>{
}
My controller has the following code:
List<Investment> investments = investmentRepo.findAll();
for(Investment investment:investments){
logger.info(" Got investment with id "+investment.getInvestmentId());
if(investment.getInvestmentType() != null){
logger.info("Investment Type is "+investment.getInvestmentType().getInvestmentTypeName());
}
else{
logger.info("null investment type ");
}
}
However, the for loop always outputs "null investment type"
So it appears that the findAll method does not retrieve the data from the InvestmentType table to which there is a OneToOne mapping.
Am I doing something wrong? Do I need to do something explicit in order to also retrieve data from the associated table with the mapping?

Answer 1

one-to-one association is the only one that can not be proxied.Add fetch type lazy and use mappedby on related table colum.
Parent table
#NotNull(message = "Cannot be empty")
#OneToOne(fetch = FetchType.LAZY, optional = false)
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "investment_type_id")
private InvestmentType investmentType;
Related table
#Id #GeneratedValue(strategy=GenerationType.AUTO)
#OneToOne(mappedBy = "investment")
private Integer investmentTypeId;