It sounds as though you are developing your database as you write
your program.
In my experience it generally works better to think very hard about
the data that your
program will use, and develop a database that will hold that data and
make it easy
to get at information your program will need often BEFORE YOU START
DOING ANY
real coding. Prototyping is a good way of getting information from
users that will help
you decide on the requirement for your data design.
In this case, if you had thought carefully in advance you would have
realized that
a customer might have multiple phone numbers, each of a specified
type (cell, fax,
work, home, etc.) and that you might want a description field (this
home phone is
only valid from May 1 - October 31).
You might also have considered the possibility that one phone
number could be
associated with multiple people (members of the same family might
share a single
home phone number). You would then have come up with a data design like
this:
create table People { PersonId, name, etc. }
create table Phone (PhoneId, name, PhoneTypeId, etc.)
create table PhoneType (PhoneTypeId, code - home, work, cell, fax, etc.)
and here is the main point
create table Person_Phone (id, PersonId, PhoneId, description)
Now that you have the data design if you generate entity tables
everything
works just fine.
Bill Gordon
On Mar 30, 2009, at 12:38 AM, poplar wrote:
>
> Hi all,
>
> I have a problem for adding a new column in OneToMany relationship
> table. I create 2 entities: Customer and Phone, 1 customer may have
> many phone, therefore I use @OneToMany annotation before Collection
> <Phone>, the result after deploying is that a table called Customer-
> Phone has been automatically created with 2 columns are the primary
> keys of Customer and Phone. Now I want to add a column for example
> Description, but I don't know how to do. Could you please help me? Any
> idea is welcome.
>
> Thanks and B.R,
> Poplar
>
> >
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