ConstraintViolationException could not execute statement; SQL [n/a]; constraint [id] - postgresql

Question

I have two entities, fileVersion and fileEnvironment, which have a many to many relationship. I'm using a junction table, modeled by fileDeployment entity.
The junction entity:
#Data
#Builder(toBuilder = true)
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(
name = "file_deployment"
)
public class FileDeploymentEntity {
#EmbeddedId
private FileDeploymentKey id;
#ToString.Exclude
#ManyToOne
#MapsId("fileVersionId")
#JoinColumn(name = "fileVersionId")
private FileVersionEntity fileVersion;
#ToString.Exclude
#ManyToOne
#MapsId("fileEnvironmentId")
#JoinColumn(name = "fileEnvironmentId")
private FileEnvironmentEntity fileEnvironment;
}
It's composite key:
#Embeddable
#NoArgsConstructor
#AllArgsConstructor
#Data
#Builder(toBuilder = true)
public class FileDeploymentKey implements Serializable {
#Column
private UUID fileVersionId;
#Column
private UUID fileEnvironmentId;
}
Its JPA repository:
#Repository
public interface FileDeploymentEntityRepository extends
JpaRepository<FileDeploymentEntity, FileDeploymentKey>,
JpaSpecificationExecutor<FileDeploymentEntity> {
}
The two entities for which the junction entity is capturing the many-to-many relationship for:
#Data
#Builder(toBuilder = true)
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(
name = "file_environment"
)
public class FileEnvironmentEntity {
#Id
#GeneratedValue(generator = "UUID")
#GenericGenerator(name = "UUID", strategy = "uuid2")
private UUID id;
#ToString.Exclude
#OneToMany(mappedBy = "fileEnvironment")
private List<FileDeploymentEntity> fileDeployments;
}
FileVersion is the other
#Data
#Builder(toBuilder = true)
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(
name = "file_version"
)
public class FileVersionEntity {
#Id
#GeneratedValue(generator = "UUID")
#GenericGenerator(name = "UUID", strategy = "uuid2")
private UUID id;
#ToString.Exclude
#OneToMany(mappedBy = "fileVersion")
private List<FileDeploymentEntity> fileDeployments;
}
The following code executes fine:
var fileDeploymentEntity = FileDeploymentEntity.builder()
.id(FileDeploymentKey.builder()
.fileVersionId(existingFileVersion.get().getId())
.fileEnvironmentId(existingFileEnvironment.get().getId())
.build())
.deploymentTime(
Instant.now(clock))
.fileEnvironment(existingFileEnvironment.get())
.fileVersion(existingFileVersion.get())
.build();
var result = fileDeploymentEntityRepository.save(fileDeploymentEntity);
But when eventually fileDeploymentEntityRepository.flush() is called I get the following exception:
could not execute statement; SQL [n/a]; constraint [id]
org.hibernate.exception.ConstraintViolationException: could not
execute statement
org.postgresql.util.PSQLException: ERROR: null value in column "id"
violates not-null constraint Detail: Failing row contains
(7670fec3-3766-4c69-9598-d4e89b5d1845,
b9f6819e-af89-4270-a7b9-ccbd47f62c39, 2019-10-15 20:29:10.384987,
null, null, null, null).
If I also call save for the 2 entities it doesn't change the result:
fileVersionEntityRepository
.save(existingFileVersion.get().addFileDeployment(fileDeploymentEntity));
fileEnvironmentEntityRepository
.save(existingFileEnvironment.get().addFileDeployment(fileDeploymentEntity));
Any help would be greatly appreciated!

Answer 1

For me the issue was that I named another entity with the same table name by accident which caused the schema that was generated to be very different from what I thought it was.
Take away lesson:
1) Check the schema that is generated when in doubt.
var con = dataSource.getConnection();
var databaseMetaData = con.getMetaData();
ResultSet resultSet = databaseMetaData.getTables(null, null, null, new String[]{"TABLE"});
System.out.println("Printing TABLE_TYPE \"TABLE\" ");
System.out.println("----------------------------------");
while(resultSet.next())
{
//Print
System.out.println(resultSet.getString("TABLE_NAME"));
}
ResultSet columns = databaseMetaData.getColumns(null,null, "study", null);
while(columns.next())
{
String columnName = columns.getString("COLUMN_NAME");
//Printing results
System.out.println(columnName);
}