如何使用JPA EclipseLink在SQL Server中生成varchar(max)列

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class MyEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(columnDefinition = "varchar(max)")
    private String myColumn;

    // 其他属性和方法
}

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class MyEntityDao {
    private EntityManagerFactory emf;

    public MyEntityDao() {
        emf = Persistence.createEntityManagerFactory("my-persistence-unit");
    }

    public void save(MyEntity entity) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        em.persist(entity);
        em.getTransaction().commit();
        em.close();
    }

    // 其他操作方法
}