如何设置@Column批注使用的precision属性？

Question

I often use java.lang.Integer as primary key. Here you can see some piece of code

@Entity
private class Person {

    private Integer id;

    @Id
    @Column(precision=8, nullable=false) 
    public Integer getId() {

    }        

}

I need to set up its precision attribute value equal to 8 . But, when exporting The schema (Oracle), it does not work as expected.

AnnotationConfiguration configuration = new AnnotationConfiguration();
configuration
    .addAnnotatedClass(Person.class)
    .setProperty(Environment.DIALECT, "org.hibernate.dialect.OracleDialect")
    .setProperty(Environment.DRIVER, "oracle.jdbc.driver.OracleDriver");

SchemaExport schema = new SchemaExport(configuration);
schema.setOutputFile("schema.sql");

schema.create(true, false);

schema.sql outputs

create table Person (id number(10,0) not null)

Always i get 10 . Is there some workaround to get 8 instead of 10?

Answer 1

Javadoc seems to indicate that parameter isn't meaningful at all for Integer.

http://java.sun.com/javaee/5/docs/api/javax/persistence/Column.html#precision%28%29

So it would appear hibernate is right to ignore it, as your column type isn't a BigDecimal etc, and just make a column that holds a 32-bit integer.

Answer 2

You could set the columnDefinition attribute.

From the Javadocs:

columnDefinition (Optional) The SQL fragment that is used when generating the DDL for the column.

@Entity
private class Person {

    private Integer id;

    @Id
    @Column( columnDefinition="number(8,0)", nullable=false) 
    public Integer getId() {

    }        

}