How to update only few fields of entity using JPA and Hibernate? - mysql

Question

I'm using MySQL DB.
My entity for the table is Account with the following fields:
id(long), balance (double), created_on(Date), currency(Enum).
When I'm doing a PUT request to update the account, I pass in the request body JSON.
I want to update, for example, only the balance, but the other columns' values to be saved.
In that case (I'm not passing the currency type) the balance is updated, but the currency has value NULL. Is that because it's enum?
I've tried using #DynamicUpdate annotation, but still, it doesn't have any change.
#RestController
public class AccountController {
#PutMapping("/accounts/{id}")
public void updateAccount(\#PathVariable long id, #RequestBody AccountDto accountDto) {
accountService.updateAccount(id, accountDto);
}
}
I'm using AccountDto (which I pass in the request body) and I'm calling the accountService
public void updateAccount(long id, AccountDto accountDto) {
Account account = accountRepository.getOne(id);
account.fromDto(accountDto);
this.accountRepository.save(account); }),
which calls the AccountRepository
public void fromDto(AccountDto accountDto) {
this.balance = accountDto.getBalance();
this.currency = accountDto.getCurrency();
}
Here is the AccountDto class:
public class AccountDto {
private long id;
#NotNull #PositiveOrZero
private double balance;
#NotNull #Enumerated(EnumType.STRING)
private Currency currency;
}

Answer 1

You need to perform a select query on Account entity and then update only the desired fields.
(Eg - making assumptions of my own of underlying method being used for accessing DB)
public updateAccount(AccountModel jsonBody) {
Account entity = accountRepository.findById(jsonBody.getAccountId());
entity.setBalance(jsonBody.getBalance());
accountRepository.save(entity);
}

Answer 2

If you get null as currency in the JSON you shouldn't update it:
So fromDto must look like:
public void fromDto(AccountDto accountDto) {
this.balance = accountDto.getBalance();
if (accountDto.getCurrency() != null) {
this.currency = accountDto.getCurrency();
}
}