Column mapping

By default, all fields (or getter methods, according to @Id place) are mapped as columns in the containing table, with a default name matching the field (or getter) name, and a default type matching its Java type, if you need to customize how a column is mapped in the database, as in the following code snippet:

@Entity 
public class Movie { 
    @Column(name = "movie_title") 
    private String title; 
    .... 
} 

In the previous example, we have customized the name of the title field to movie_title. Moreover, the previous example maps by default to the database type VARCHAR. As you know, VARCHAR types have a length. The default length of a VARCHAR field in JPA is 255, but you can customize this value by using the length attribute:

@Entity 
public class Movie { 
    @Column(name = "movie_title", length=100) 
    private String title; 
    .... 
} 

If you have a text type available in your database, you can also modify the default type by using the columnDefinition attribute:

@Entity 
public class Movie { 
    @Column(name = "movie_title", columnDefinition = "text") 
    private String title; 
    .... 
} 

Other attributes are available for the customization of table columns, as shown in the following table: