PostgreSQL : Support Enum persisted as datastore enum about datanucleus-rdbms HOT 1 OPEN

For PostgreSQL this would be
CREATE TYPE my_gender AS ENUM ('Male','Female')
Create a table using this type, like this
CREATE TABLE PERSON (ID INT NOT NULL, GENDER my_gender NOT NULL);
Insert into the table
INSERT INTO PERSON (ID, GENDER) VALUES (1, 'Male');

To implement this we need to be able to annotate an Enum with something like

@EnumNative("my_gender")
public enum Gender
{
    MALE,
    FEMALE
}

and then at schema generation time it would need to look at the Enum and see the type name and issue
CREATE TYPE my_gender AS ENUM ('MALE', 'FEMALE')
and subsequently any usage of that Enum needs to use 'my_gender' SQL type.

For the sake of completeness, for MySQL this would be

CREATE TABLE MY_TABLE (
    ...
    size ENUM('x-small', 'small', 'medium', 'large', 'x-large')
);

and insert would be
INSERT INTO MY_TABLE (... , size) VALUES (... ,'large'), (... ,'medium'), (... ,'small');
BUT that is effectively the same as using ANSI standard "CHECK IN (...)" so we will not support it there, just for PostgreSQL.

from datanucleus-rdbms.