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javahibernateannotationsindexingmysql-error-1170

Hibernate @Index error on long string columns

I have a data model where I need a String column to be indexed by the backing database: 

@Entity
public class A {
    // ... 

    @Column(length=2048)
    @Index(name="strFieldIndex")
    private String strField;
}

When adding the length attribute of @Column(length=2048) (for which hibernate doesn't generate varchar anymore) the following error message appears on MySQL: 

ERROR org.hibernate.tool.hbm2ddl.SchemaExport - 
    BLOB/TEXT column 'strField' used in key specification without a key length

I've scanned the API docs for hibernate and I can't find an approach to setting the key length.

Solution

  • I think you have to declare this index manually as required for MySQL, since Hibernate can't handle all DBMS-specific requirements. For example, using <database-object> syntax.