auto_increment primary key

[Qi Liang]

I have created a CMP entity bean with an auto_increment primary key in it's table with JBoss 3.2.3 and mySQL. Now I can insert new row into table with the auto_increment key successfully! But I want to know the auto_increment key value after bean creating. So I called EntityContext.getPrimaryKey() in ejbPostCreate() and printed it. But I found the key always is zero.(I set it zero when calling ejbCreate())

I want to know how to get the mySQL generate key in my code.

Thanks in advance!

Cliff Liang

[Nathaniel Stoddard]

When you have JBoss have MySQL autogenerate the key (when the insert happens), you shouldn't set the primary key value at all. Just return null and that's it. Don't do anything else. JBoss will retrieve the value from MySQL and set the primary key value for you.

As for how to do this, search this forum. I remember answering this question a while ago.

[Qi Liang]

The following is my bean UserBean:
Long id
String username
String name

public Long ejbCreate(String username, String name)
{
this.setId(new Long(0));
this.setUsername(username);
this.setName(name);
return null;
}

At first, I didn't write "this.setId(new Long(0));" as above, JBoss always print error in its console, saying "Primary key can not be null". But new row is inserted into database. After adding this statement, no error appears, and everything is ok.

So I think this statement take some role while creating.

My question is whether I can get the generated key after creating. As so far, I think it's impossible to get it, right?

[Nathaniel Stoddard]

Did you search the forum? Or the Internet? I'm not going to give you all the answers, but if you spend about 10 more minutes of your time you can make everything crysal-clear for yourself.

[Qi Liang]

I search it in Internet, and I also see the source of mysql-generated-key. But from the interface of EntityContext, I think if the primary key is not assigned automatically, I will never get it.

[Victor J. Lu]

Have a try this:

https://coderanch.com/t/88598/JBoss/JBoss-CMP-auto-increment-not

I got the same error as you. (using Lomboz)

Remember change jboss version to 3.2 in "xdoclet.xml" to 3.2

-------------------
Victor J. Lu
BTech IT
UoA
[ August 23, 2004: Message edited by: Victor J. Lu ]