How to Ensure Hibernate Preserves Enum Values When Mapping to a MySQL Enum Column?

Preserving Enum Values in Hibernate: Troubleshooting Wrong Column Type

In the realm of data persistence, ensuring the compatibility between data models, database schemas, and their respective mappings is essential. When working with enumerated types in Java, it's crucial to establish how Hibernate maps these enums to the underlying database.

In your case, you've defined a MySQL column as an enum and created a corresponding enum in your Java code. However, you're encountering the following error: "Wrong column type in MyApp.Person for column Gender. Found: enum, expected: integer." This error arises when Hibernate expects the Gender column to be an integer due to the enum being treated as an ordinal or a string, depending on the @Enumerated annotation's specification.

To resolve this issue, you can explicitly specify the column's definition using the columnDefinition attribute:

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

By providing a column definition, you instruct Hibernate not to guess the column type but to adhere to the specified definition.

Alternatively, if you're not using Hibernate to generate your schema, you can remove the need for column definition values by setting them to arbitrary values:

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

In this way, you can ensure that the enum values are preserved in your Java enum while synchronizing your Liquibase or SQL scripts accordingly.

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