How to Preserve Enum Type in Hibernate When Working with MySQL\'s `enum` Column?

Enum Persistence in Hibernate: Preserving Enum Type

Problem

Consider the following setup: a MySQL table with a column defined as "gender enum('male', 'female')", a corresponding Java enum "Gender", and a Person entity with "Gender gender". When attempting to boot the application, an error is encountered: "Wrong column type in MyApp.Person for column Gender. Found: enum, expected: integer."

Cause and Solution

By default, Hibernate expects enumerated fields to be stored as integers. To specify that the enum type should be maintained in the database, use the following annotations:

<code class="java">@Column(columnDefinition = "enum('MALE','FEMALE')")
@Enumerated(EnumType.STRING)
private Gender gender;</code>

Alternatively, if you prefer to delegate schema generation to Liquibase or an SQL script, you can provide a dummy value for the columnDefinition:

<code class="java">@Column(columnDefinition = "enum('DUMMY')")
@Enumerated(EnumType.STRING)
private ManyValuedEnum manyValuedEnum;</code>

This ensures that Hibernate will rely on the Java enum and the database schema synchronization tools to maintain the correct enum values.

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