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amphibient
amphibient

Reputation: 31212

Mapping enum to table column where DB value is enum field, not label

My enum looks something like this

public enum EventType {

    DATASET_DELETION("DSDEL");

    private static final Map<String, EventType> dbIdLookup = new HashMap<>();

    static {
        for (EventType type : EnumSet.allOf(EventType.class)) {
            String databaseID = type.getId();
            dbIdLookup.put(databaseID, type);
        }
    }

    private String id;

    EventType(String _id) {

        this.id = _id;
    }

    public String getId() {
        return this.id;
    }

    public EventType getFromDatabaseID(String _databaseID) {

        EventType result = dbIdLookup.get(_databaseID);

        return result;
    }
}

where DATASET_DELETION is what I would like to refer to the field value in the java code and DSDEL is the value I want to map it to in the database. I want the database code to be more compact and the java label more readable.

My current mapping doesn't work:

@Column(name = "EVENT_TYPE")
private EventType type;

Throwing 

java.lang.RuntimeException: java.lang.IllegalArgumentException: Unknown name value for enum class blah.blah.EventType: DSDEL

How can I map an enum to a database value that is not the primary label of the enum but one of its fields in the declaration?

Upvotes: 0

Views: 469

Answers (1)

Neil Stockton
Neil Stockton

Reputation: 11531

JPA does not support arbitrary enum values, only providing support for "ordinal" or "name" persistence. Improvements have been requested for inclusion in JPA 2.2+ but who knows when (if) that will happen.

One way (that is portable) would be to provide a JPA AttributeConverter for that Enum type, so it converts the Enum to a String, and persists the arbitrary String value you have internally.

Some JPA providers support custom handling, like this one in DataNucleus JPA. Maybe your provider has something also?

Upvotes: 1

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