h3. Given
{code:java}@Entity
@Table(uniqueConstraints = @UniqueConstraint(name = "uk_b_a", columnNames = { "b", "a" }))
class TestEntity {
@Id
private Long id;
private String b;
private String a;
}{code}
Note that we define an explicit unique constraint on the columns *(b, a)* (in that very order). The column order could be important since the underlying unique index should be used to speed-up queries that select all entities for a given value of “b”.
h3. Actual vs. Expected
When the schema gets created in the context of a JPA EntityManagerFactory, the columns are (re-)ordered during construction of the [SessionFactoryImpl, Line 252: bootMetamodel.orderColumns( false )|https://github.com/hibernate/hibernate-orm/blob/58aff00957721074a4a3937256edd64a067bc943/hibernate-core/src/main/java/org/hibernate/internal/SessionFactoryImpl.java#L252]
This leads to the following DDL:
{code:sql}create table "TestEntity" (
id bigint not null,
a varchar(255),
b varchar(255),
primary key (id),
constraint uk_b_a unique (a, b)
);{code}
Note that “uk_b_a” is created with columns {color:#bf2600}*(a, b)*{color} instead of the expected column order *(b, a)*.
h3. Workaround
One can restore the behavior of Hibernate 6.1 by switching to the legacy column ordering strategy via {{hibernate.column_ordering_strategy=legacy}}.
h3. Test Case
_Upcoming [https : I’ll submit a PR with a unit test for this issue //github . _ com/hibernate/hibernate-orm/pull/7007|https://github.com/hibernate/hibernate-orm/pull/7007|smart-link] |
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