Or, if you want a sollution thats free and lots easier, look at your java
SDK docs at java.rmi.server.UID class.
One of the major critisims of EJB as it currently exists is that it can't
take advantage of a databases "serial" or "autoincrement" field. Of course,
these all vary from database to database anyhow, and EJB is not even tied
to a relational database.
So using a primary key generator is a necessity if you can't create your PK
from your data (maybe by combining other fields).
Good luck!
Jim
--On Friday, May 04, 2001 10:47 AM +0100 Jim Downing <[EMAIL PROTECTED]>
wrote:
> Check out www.activescript.co.uk for a non-free ($99) component to
> generate unique ids. The author has also posted the pattern on
> theserverside.com, so you have something to work to if you want to
> implement it yourself.
>
> jim
>
> ----- Original Message -----
> From: "Ralph Jensen" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Friday, May 04, 2001 10:25 AM
> Subject: Re: [JBoss-user] EJB question
>
>
>> The portability would be there in terms of data access. How to tell the
>> database to autoincrement when I create a table is probably always
> database
>> specific. Or not?
>>
>> I'm not good at SQL. So how would your suggestion look in code? What
>> would the key generator bean look like? Off which table would it work?
>>
>> Ralph
>>
>> ----- Original Message -----
>> From: Vinay Menon <[EMAIL PROTECTED]>
>> To: JBOSS <[EMAIL PROTECTED]>
>> Sent: Friday, May 04, 2001 4:29 PM
>> Subject: Re: [JBoss-user] EJB question
>>
>>
>> Why don't you just use a primary key generator bean to encapsulate the
>> key genaration? The ejbCreate can then work off that ejb and assign the
> primary
>> key field to the primary key generated field? so your autoincrement
>> essentially will not be on the same table as the ejb but a different one
>> and the primary key generator will work off that table. [Also makes sure
>> that you have complete protability in terms of the database server!]
>>
>> Vinay
>>
>>
>>
>> ----- Original Message -----
>> From: Ralph Jensen
>> Sent: Friday, May 04, 2001 8:52 AM
>> To: [EMAIL PROTECTED]
>> Subject: [JBoss-user] EJB question
>>
>>
>> I asked this question elsewhere, but didn't get an answer. So:
>>
>> An entity bean's ejbCreate(...) method MUST return the primary key. That
> is
>> not a problem, if I specify the primary key myself and pass it to the
>> create(...) method.
>>
>> But I want to let the database assign the primary key by creating a table
>> with an AUTOINCREMENT default for the primary key column, like in this
>> example using Cloudscape (part of SUN's J2EE v1.3):
>>
>> create table myTable(
>> id INT DEFAULT AUTOINCREMENT CONSTRAINT pk_id PRIMARY KEY,
>> someString VARCHAR(6),
>> etc.
>> );
>>
>> Then I can use INSERT like this:
>> INSERT INTO mytable ( someString ) VALUES ( 'Hello' );
>>
>> The database then assigns a unique value to the id column of that new
>> record.
>>
>> If I do this in the ejbCreate(...) method of my bean my problem is: How
>> do I know that value in order to return it? Is that possible?
>>
>> Thanks
>>
>> Ralph Jensen
>>
>>
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********************************************
I shall be telling this with a sigh
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And that has made all the difference.
- Robert Frost, 1916
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