I'm using the org.hibernate.annotations. {{@ CreationTimestamp }} and {{@ UpdateTimestamp }} annotations as examples, heading towards similar annotations that use a in-database value using {{ current_timestamp }} . As the first step I want to show that {{ @CreationTimestamp }} , {{ @UpdateTimestamp }} and {{ @DynamicUpdate }} annotations work together.
As my starting point In TestEntity.java (attached) I've added {{ @CreationTimestamp }} to the createdDate data member and {{ @UpdateTimestamp }} to the lastModifiedDate data member.
The database table is:
{code}
CREATE TABLE TestEntity
(
id bigserial NOT NULL,
version bigint NOT NULL,
createdDate timestamp(6) NOT NULL,
lastModifiedDate timestamp(6) NOT NULL,
value int NOT NULL,
CONSTRAINT PK_TestEntity PRIMARY KEY (id)
);
{code}
On creation of a TestEntity the expected SQL is created:
{noformat}
Hibernate:
insert
into
TestEntity
(createdDate, lastModifiedDate, value, version)
values
(?, ?, ?, ?)
{noformat}
On update of the TestEntity, by modifying just the value data member, the update statement is also as expected:
{noformat}
update
TestEntity
set
lastModifiedDate=?,
value=?,
version=?
where
id=?
and version=?
{noformat}
Note that I seem to need to define {{ @Column(insertable=true, updatable=false) }} annotation for the createdDate data member otherwise it is rewritten on updates to the entity (not sure if this is expected or not).
If I then uncomment the {{ @DynamicUpdate }} in TestEntity.java, recompile and rerun the test I get the following SQL generated:
Hibernate:
{noformat}
insert
into
TestEntity
(createdDate, lastModifiedDate, value, version)
values
(?, ?, ?, ?)
{noformat}
Hibernate:
{noformat}
update
TestEntity
set
value=?,
version=?
where
id=?
and version=?
{noformat}
So it looks like {{ @DynamicUpdate }} doesn't detect that the lastModifiedDate data member is a generated value and should be recorded in the database when the row is being updated in the database.
I run into additional problems when I replace the {{ @CreationTimestamp }} and {{ @UpdateTimestamp }} annotations with custom ones that generate the value in the database by using {{ current_timestamp }} (which is my ultimate goal) but I will post them separately after I have confirmation that my understanding of this first problem is correct. |
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