I'm working on a web project using:
- Spring 4.x (Spring Boot 1.3.3)
- Hibernate 4.x
- PostgreSQL 9.x
I'm new to Postgres DB and for my tables I decided to use (for the first time) UUID
identifiers, but I'm having some troubles...
For ID field I used Postgres uuid
type and I set as default value uuid_generate_v4()
. All works correctly when I generate a new row directly by a PSQL insert, but I cannot create a new record by my application.
As an example, this is how I declared an entity in my application:
@Entity
@Table(name = "users")
public class User {
@Id
@Type(type = "pg-uuid")
private UUID id;
// other fields and methods...
}
For this declaration I'm using the Type
Hibernate annotation.
Find operations work well, but when I try to make an insert I get this exception:
org.springframework.orm.jpa.JpaSystemException: ids for this class must be manually assigned before calling save(): net.myapp.User;
Followiong this tutorial I tried to solve the issue. I changed my entity definition to:
@Entity
@Table(name = "users")
public class User {
@GeneratedValue(generator = "uuid2")
@GenericGenerator(name = "uuid2", strategy = "uuid2")
@Column(columnDefinition = "BINARY(16)")
@Id
private UUID id;
// other fields and methods...
}
But now I'm getting wrong ID values when I retrieve (existing) data from DB (still haven't tried insert...).
So what is the right way to define ID field in my case?
UPDATE
Using the second definition...
When I try to find by ID, I'm getting:
org.postgresql.util.PSQLException: ERROR: operator does not exist: uuid = bytea Hint: No operator matches the given name and argument type(s). You might need to add explicit type casts.
When I try to create new record:
org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute statement; SQL [n/a];