Mapping Java Enum in Postgresql with Spring Data JDBC

Question

I want to be able to map a enum declared in java to an enum created in postgres. For example having the following:

CREATE TYPE EYE_COLOR AS ENUM ('BROWN', 'BLUE', 'GREEN');
CREATE TABLE PERSON (
    ID       INT PRIMARY KEY AUTO_INCREMENT,
    NAME     NVARCHAR2(128) NOT NULL,
    EYE      EYE_COLOR
);

In java I have something like this:

public enum EyeColor {
    BROWN,
    BLUE,
    GREEN
}
public class Person {
    @Id
    Long id;
    String name;
    EyeColor eye;
}

When I try to do save something to the database like this:

personRepository.save(new Person("test", EyeColor.BROWN))

the sql log seems fine:

Executing prepared SQL statement [INSERT INTO person (name, eye) VALUES (?, ?)]
 o.s.jdbc.core.StatementCreatorUtils      : Setting SQL statement parameter value: column index 1, parameter value [test], value class [java.lang.String], SQL type 12
 o.s.jdbc.core.StatementCreatorUtils      : Setting SQL statement parameter value: column index 2, parameter value [BROWN], value class [java.lang.String], SQL type 12

but inside the actual database field I get an exception text:

org.h2.jdbc.JdbcSQLException: General error: "java.lang.RuntimeException: type=25" [50000-196]  
at org.h2.message.DbException.getJdbcSQLException(DbException.java:345)     
at org.h2.message.DbException.get(DbException.java:168)     
at org.h2.message.DbException.convert(DbException.java:295)     
at org.h2.message.DbException.toSQLException(DbException.java:268)  
at org.h2.message.TraceObject.logAndConvert(TraceObject.java:352)   
at org.h2.jdbc.JdbcResultSetMetaData.getColumnClassName(JdbcResultSetMetaData.java:376)     
at com.intellij.database.remote.jdbc.impl.RemoteResultSetImpl.getObject(RemoteResultSetImpl.java:1269)  
at com.intellij.database.remote.jdbc.impl.RemoteResultSetImpl.getCurrentRow(RemoteResultSetImpl.java:1249)  
at com.intellij.database.remote.jdbc.impl.RemoteResultSetImpl.getObjects(RemoteResultSetImpl.java:1229)     
at sun.reflect.GeneratedMethodAccessor13.invoke(Unknown Source)     
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)    
at java.lang.reflect.Method.invoke(Method.java:498)     
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:346)  
at sun.rmi.transport.Transport$1.run(Transport.java:200)    
at sun.rmi.transport.Transport$1.run(Transport.java:197)    
at java.security.AccessController.doPrivileged(Native Method)   
at sun.rmi.transport.Transport.serviceCall(Transport.java:196)  
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)     
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)     
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)     
at java.security.AccessController.doPrivileged(Native Method)   
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)  
at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.RuntimeException: type=25

If I replace the EYE_COLOR type to NVARCHAR2(128) in the postgres column definition everything works fine. An actual "BROWN" value is inserted.

Any ideas how this should be implemented?

LE: Forgot to add my spring database driver:

spring.datasource.driver-class-name=org.h2.Driver
spring.datasource.url=jdbc:h2:file:path/to/file;DB_CLOSE_DELAY=-1;MODE=PostgreSQL;AUTO_SERVER=TRUE

I also tried using the ENUM definition like they say in the H2 driver specifications directly inside the column definition, but is still didn't work:

CREATE TABLE PERSON (
     ID       INT PRIMARY KEY AUTO_INCREMENT,
     NAME     NVARCHAR2(128) NOT NULL,
     EYE      ENUM ('BROWN', 'BLUE', 'GREEN')
);

The stacktrace says h2 all over the place, but your tag says postgresql. So which is it? — Jens Schauder, Nov 07 '18 at 13:50
https://jira.spring.io/browse/DATAJDBC-239 seems to be related. Especially since says treating it as a String is fine: https://stackoverflow.com/questions/40356750/java-postgres-enums-how-do-i-make-them-work-together-for-update — Jens Schauder, Nov 07 '18 at 14:08
Thanks for the quick answer, for the time being we'll use the string solution. — Razvan S, Nov 07 '18 at 14:31
I assume you use h2 for testing and postgres in production. If this is the case I recommend switching to Testcontainers. — Jens Schauder, Jun 04 '20 at 10:35

score 1 · Answer 1 · answered Jun 04 '20 at 07:02

Currently there is no special support for Postgres enums in Spring Data JDBC.

But as described here: https://stackoverflow.com/a/40356977/66686 Postgres enums would need some special SQL syntax to get manipulated.

This allows for the following possible solutions of the problem:

use a VARCHAR instead of an ENUM in the database
use a @Query annotated method using the special syntax for the enum. This is only feasible if your aggregate consists only of a single entity.

Is it not https://github.com/spring-projects/spring-data-jdbc/issues/629 ? — gstackoverflow, Jan 21 '22 at 09:00

score 0 · Answer 2 · answered Jun 02 '22 at 15:19

We solved this problem in different ways.

The first way - use flag stringtype=unspecified (see https://jdbc.postgresql.org/documentation/94/connect.html)

jdbc:postgresql://${PG_HOSTNAME}/${PG_DB_NAME}?stringtype=unspecified

More info see this https://jdbc.postgresql.org/documentation/94/connect.html

The second way - use operator functions to automatically transform between enums and varchar. We will have to do this for each enum data type example for your enum eye_color.

create or replace function
        eye_color_with_character_varying_equals(_a eye_color, _b character varying)
    returns boolean as
    $$
        select _a = _b::eye_color
    $$
    language sql
    immutable strict;

create operator = (
    leftarg = eye_color,
    rightarg = character varying,
    procedure = eye_color_with_character_varying_equals,
    negator = !=,
    hashes,
    merges
    );
create cast ( character varying as eye_color) with inout as assignment;

The third way - use @Query for special syntax.

Mapping Java Enum in Postgresql with Spring Data JDBC

2 Answers2

Linked