Generating entity classes from database - question

[mn1247]

I have a question about entity beans. Suppose I have two tables that have a one-to-many relationship. Let's say, Table A is on the "one" side and Table B is on the "many" side.

If I use the NB "Entities from database" wizard, I seem to only get a bean generated for Table A. Table B does not result in an entity class, and the wizard just says "no primary key" when I try to select it for inclusion.

Is this how it's supposed to be? Should only Table A get an entity class? Or is something going wrong?

Thanks
Eric

[Antonio Varela]

On Fri, Jan 28, 2011 at 8:51 AM, mn1247 <address-removed> wrote:

[edwin]

Hi Eric,

I believe both tables need to have a primary key defined. In addition the foreign key constraint should be defined in the database so that the related table automatically gets picked up. I just tested it and it worked for me.

Composite keys are also possible but I am not sure if this works with the wizard. In any case the primary key should be defined.

[mn1247]

Thanks for the response. Here's an example (simplified for clarity) of the tables I'm using. They both seem to have primary keys.

Where am I going wrong?

Eric


The "one" table….


CREATE TABLE `tblaxis1` (
`DSMCodeID` mediumint(9) DEFAULT NULL,
`PKID` mediumint(9) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`PKID`),
KEY `DSMCodeID` (`DSMCodeID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

The "many" table...

CREATE TABLE `lstdsmcodes` (
`PKID` mediumint(9) NOT NULL AUTO_INCREMENT,
`DSMCodesID` mediumint(9) NOT NULL,
PRIMARY KEY (`PKID`),
KEY `DSMCodesID` (`DSMCodesID`),
CONSTRAINT `lstdsmcodes_ibfk_1` FOREIGN KEY (`DSMCodesID`) REFERENCES `tblaxis1` (`DSMCodeID`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

[edwin]

I tried it with your tables as well and both entity classes were generated by the wizard so there must be something wrong with your installation. I use 6.9.1 as well.

On a side note, I think you foreign key does not make sense. It is not a one to many relationship as it does not refer to the primary key in the other table. A typical one to many relationship would be the following where the country_id in the person table refers to the id of the country table.

PERSON
id (PK)
name
country_id (FK)

COUNTRY
id (PK)
name