Does Hibernate 3.2 support generating Database schema from a

[legolas.w]

Hi
Thank you for reading my post
I am reading pro Hibernate 3.0 and it says that Hibernate 3 does not support generating database schema from the annotated java classes.
is it supported in Hibernate 3.2 ?
if yes, how i can do it?

thanks

[andydale]

Yes Hibernate can create the DB schema from annotated classes, consider the following class

@Entity
@Table(name = "Student")
@SequenceGenerator(name = "Student_Sequence", initialValue = 1, allocationSize = 1, sequenceName = "student_seq")

public final class Student {
 //************** class variables *****************
 /**
 * The ID of the entity.
 */
 private int mId;

 /**
 * Name of the student.
 */
 private String mName;


 /**
 * Course student is enrolled on
 */
 private Collection<Course> mCourses = new ArrayList<Course>();
 //************************************************

 //*********** getters and setters ****************

 /**
 * Return the courses the student is enrolled on.
 * @return mCourses courses
 */
 @ManyToMany(mappedBy = "students", fetch = FetchType.EAGER, cascade ={CascadeType.PERSIST, CascadeType.MERGE})
 public Collection<Course> getCourses() {
 return mCourses;
 }

 /**
 * See the course the student is enrolled on
 * @param pCoursesEnrolledOn courses
 */
 public void setCourses(final Collection<Course> pCourses) {
 mCourses = pCourses;
 }

 /**
 * get the Id.
 * @return mId id
 */
 @Id
 @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "Student_Sequence")
 @Column(name = "student_id")
 public int getId() {
 return mId;
 }

 /**
 * Set the id.
 * @param pId id
 */
 public void setId(final int pId) {
 this.mId = pId;
 }

 /**
 * Return the name.
 * @return mName name
 */
 public String getName() {
 return mName;
 }

 /**
 * set the name.
 * @param pName name
 */
 public void setName(String pName) {
 this.mName = pName;
 }
 //************************************************
}

will create a table on deploy with the definition

CREATE TABLE student
(
 student_id int4 NOT NULL,
 name varchar(255),
 CONSTRAINT student_pkey PRIMARY KEY (student_id)
)

The above example is pretty simple, but you could just deploy a class annotated with @Entity. On deploy JBoss/Hibernate would convert it into a DB table in the DB specified in a persistence.xml file (must be in META-INF of ejb.jar).

Experiment a bit, and possibly buy yourself the Enterprise JavaBeans 3.0 book (Bill Burke, Richard Monson-Haefel), as it gives you some decent examples of how EJB3 works.


Cheers,

Andy

[legolas.w]

Hi
Thank you for your reply.
I have already a book named Pro hibernate 3.0, In that book author said that hibernate 3.0 does not support generating schema from annotated class.
and it just generate database from mapping files.

Now i learned that a ANT task helps to generate schema from mapping files.
what i want to know is about ant task or a solution for generating schema from annotated classes.

So, is there any ant task for this?
Thanks

[andydale]

Hi,

I do not know if there is an Ant task for this, i just let JBoss do it for me on deployment of my .ear file.

Andy