Re: constraint problem in oracle

Both questions are really the same. When you create a foreign key Oracle assumes that you are creating it to the primary key on the other table. If you are using a unique constraint, then you have to specify the columns that make up the Unique key.

As for an optional foreign key. Just make the fields in the child table nullable.

--
Robert Fazio, Oracle DBA
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"Sunny" <sunnyb_at_vendtek.bc.ca> wrote in message
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> Hi everyone

>

> How can you create One-to-many (optional relationship) in Oracle, like i

> mean how can you specify your constraint on an optional relationship. I

> tried to put the primary from one table to another table but didnt specify

> that it references to another table, that works but I was wondering if

 there


> is any other way in Oracle i can do it. so it  will be one to many

> relationship but optional what do i have to set in the contraints tab.

>

> One more question, when you set a foreign key in a table can it be null or

> not.

>

> thanks a lot

>

> Sunny Bagri

> Oracle Developer

>

>