Spring Data JPA JpaRepository.save(entity) not returning database default values

Question

I have a fairly simple problem. In a single transaction, my code looks something like this:

MyClass c = new MyClass();
c.setPropA("A");

c = myClassRepository.save(c);

c.setPropC("C");

Where my entity looks like this:

@Entity
@Table(name = "MY_CLASS")
public class MyClass {
  private String propA;
  private String propB;
  private String propC;

  @Id
  @Column(name = "PROP_A", unique = true, nullable = false, updatable = false)
  public String getPropA() { return propA; }
  public void   setPropA(String propA) { this.propA = propA; }

  @Column(name = "PROP_B", insertable = false)
  public String getPropB() { return propB; }
  public void   setPropB(String propB) { this.propB = propB; }

  @Column(name = "PROP_C")
  public String getPropC() { return propC; }
  public void   setPropC(String propC) { this.propC = propC; }
}

And the database is set up like this (Dialect = Oracle 11G)

CREATE TABLE MY_CLASS {
  PROP_A VARCHAR2 NOT NULL PRIMARY KEY,
  PROP_B VARCHAR2 DEFAULT 'B' NOT NULL,
  PROP_C VARCHAR2
}

So, based on the code to persist the entity, I would think I'd get queries that look something like this:

MyClass c = new MyClass();
c.setPropA("A");

c = myClassRepository.saveAndFlush(c);
// INSERT INTO MY_CLASS (PROP_A, PROP_C) VALUES ("A", NULL)
// SELECT PROP_A, PROP_B, PROP_C FROM MY_CLASS -- to refresh `c`

c.setPropC("C");

// After transaction ends, flush change to `c.propC`
// UPDATE MY_CLASS SET PROP_B = "B", PROP_C = "C" WHERE PROP_A = "A"

... but the SELECT never happens. Why is the entity not refreshed?

This breaks because of the UPDATE that (immediately) follows the INSERT and c.propB is still null. I get a ORA-01407: cannot update ("MY_SCHEMA"."MY_CLASS"."PROP_B") to NULL stack trace.

I realize there are ways around this using @PrePersist or setting default values on columnDefinition in Java, but I shouldn't have to duplicate defaults.

Note: This worked before when I was using org.hibernate.Session.saveOrUpdate() instead of Spring Data JPA for this action.

Thanks in advance for any help!

Answer 1

Hibernate doesn't know that B is generated by the database, and that it has to read it after insert, unless you tell it to do so using the @Generated annotation.