Why cant JPA/hibernate map to MySQL blob type?

Question

I got the following error

Caused by: org.hibernate.HibernateException: Wrong column type in TestTable for column PAYLOAD. Found: blob, expected: tinyblob
    at org.hibernate.mapping.Table.validateColumns(Table.java:284)
    at org.hibernate.cfg.Configuration.validateSchema(Configuration.java:1174)
    at org.hibernate.tool.hbm2ddl.SchemaValidator.validate(SchemaValidator.java:139)
    at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:387)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1385)
    at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:954)
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:883)
    ... 60 more

The column hibernate is complaining about is declared as

private byte[]  messagePayload;

@Column(name="PAYLOAD")
public byte[] getMessagePayload() {
        return messagePayload;
}

public void setMessagePayload(byte[] messagePayload) {
 this.messagePayload = messagePayload;
}

The table in the MySQL table is declared as a BLOB type. Why doesnt Hibernate want to map to it and why does it insist that i use TINYBLOB?

Thanks

Answer 1

You could try to set explicitly the type blob with columnDefinition attribute. Like this:

@Column(name="PAYLOAD",columnDefinition="blob")

Or use the @Lob annotation:

@Column(name="PAYLOAD")    
@Lob(type = LobType.BLOB)

Answer 2

@Column(columnDefinition="blob") 

Did not work for me. My specifications: - JPA - Hibernate - MySQL

Solution:

ALTER TABLE `my_table_name` CHANGE `my_column` `my_column` LONGBLOB default NULL;

public MyClass {
   @Lob
   @Column(length=100000)
   private byte[] myBlob;
}