JPA - How to set string column to varchar(max) in DDL

问题

With JPA, DDL-generation for the attribute:

@Column
final String someString;

will be someString varchar(255) null

@Column(length = 1337)
final String someString;

will yield someString varchar(1337) null.

But how can I get it to produce someString varchar(max) null?

Is it possible using the length-attribute, or do I need to use the columnDefinition-attribute?

回答1:

Some months have passed, new knowledge acquired, so I'll answer my own question:

@Lob
@Column
final String someString;

yields the most correct result. With the version of hbm2ddl I'm using, this will be transformed to the type text with SqlServerDialect. Since varchar(max) is the replacement for text in newer versions of SQL Server, hopefully, newer versions of hbm2ddl will yield varchar(max) instead of text for this type of mapping (I'm stuck at a quite dated version of Hibernate at the moment..)

回答2:

Since length is defined in the JPA spec and javadocs as int type and max is not an int then it's safe to assume that you're consigned to the columnDefinition datastore-dependent route. But then varchar(max) is datastore-dependent anyway.

回答3:

You Can Use this Code -

Model Code:

@NotNull  
@Length(max = 7)  
@Column(name = "Gender")  
private String gender;

SQL Output is like-

> gender varchar(7)

回答4:

Use @Size(max = 1337). It does generate varchar(1337)

来源：https://stackoverflow.com/questions/16414215/jpa-how-to-set-string-column-to-varcharmax-in-ddl