How to make a field as an Autogenerated

mahesh_yamsani · **Joined:** Fri Sep 04, 2009 10:04 am **Posts:** 10

Hi, can any one help me in making a field as an auto increment, I am using my application as to support all three database My-SQL, Postgres, and Oracle

tarun walia · **Joined:** Sat Aug 01, 2009 5:28 am **Posts:** 42

may be

<generator class="native"/>
It picks identity, sequence or hilo depending upon the capabilities of the underlying database.

mahesh_yamsani · **Joined:** Fri Sep 04, 2009 10:04 am **Posts:** 10

I need Using JPA, I solved that

@SequenceGenerator(name="objectscope",sequenceName="object_scope_sequence")
@GeneratedValue(generator="objectscope")

tarun walia · **Joined:** Sat Aug 01, 2009 5:28 am **Posts:** 42

Awesome!

Cameron McKenzie · **Posted:** Mon Sep 07, 2009 7:41 am

Quote:

javax.persistence.GenerationType.Sequence

Some database vendors support the use of a database sequence object for maintaining primary keys. To use a sequence, you set the GenerationType strategy to SEQUENCE, specify the name of the generator annotation, and then provide the @SequenceGenerator annotation that has attributes for defining both the name of the sequence annotation, and the name of the actual sequence object in the database.

Here's what the getId() method of the Snafu class would look like if we used a SEQUENCE GenerationType:

Code:

@Id
@SequenceGenerator(name="s1", sequenceName="SEQ")
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="s1")
public long getId() {return id;}

http://www.hiberbook.com/HiberBookWeb/learn.jsp?tutorial=12oneclasstoonetablejpamapping

mahesh_yamsani · **Joined:** Fri Sep 04, 2009 10:04 am **Posts:** 10

I hope GenerationType.SEQUENCE is only for oracle, it will not be help full for MySQL and others, at that time we should write the conditioanl based code, if we use

Code:

@GeneratedValue(generator="objectscope")

, it should works for all DBS, I tested in MYSQL. Oracle and POSTGres