Annotation to generate char() instead of varchar()

angusgr · **Joined:** Wed Feb 18, 2009 5:03 pm **Posts:** 5

Hibernate version: 3.3.1.GA
Mapping documents: persistence.xml
Name and version of the database you are using: MS SQL 2005

I'm wondering if there is an annotation to have hbm2ddl generate a char() instead of a varchar() column type (without using columnDefinition.)

So, if I have a field like:

Code:

@Column(name="bork", length=4, nullable=false)   
private String bork;

Is there a way to get the column definition from hbm2ddl as

Code:

bork char(4) not null,

instead of

Code:

bork varchar(4) not null,

apart from using

Code:

@Column(name="bork", length=4, nullable=false,columnDefinition="char(4)")

Thanks for any/all help. :).

littypreethkr · **Posted:** Thu Feb 19, 2009 2:25 am

columnDefinition is for overriding the sql DDL fragment for a particular column. I dont know any other solution.

mmerder · **Posted:** Thu Feb 19, 2009 6:23 am

If you want that Strings are always stored as char(), you have to subclass your dialect, e.g.:

Code:

import java.sql.Types;

import org.hibernate.dialect.MySQL5InnoDBDialect;


public class OwnDialect extends MySQL5InnoDBDialect {

    public OwnDialect() {
        super();
        
        registerColumnType( Types.VARCHAR, "char" );
        //the "255" marks the maximum length, for that this type should be used.
        registerColumnType( Types.VARCHAR, 255, "char($l)" );
    }
}

angusgr · **Joined:** Wed Feb 18, 2009 5:03 pm **Posts:** 5

Thanks guys, that's great. I didn't know about the length overload on registerColumnType, that's great.

Because most of the fields I wanted as char() are less than 5 characters long, I tried this:

Code:

// Default to type "char" for fields of 4 characters or less, default to "varchar" otherwise
registerColumnType( Types.VARCHAR, "varchar($l)");
registerColumnType( Types.VARCHAR, 4, "char($l)");

And I get "varchar()" for anything defined as 5 characters or more (unspecified length as varchar(255), char() otherwise. )