I have the table structure as follows

Table A
A_ID primary Key
A_col1
A_col2

Table B
B_ID Primary Key
B_col1
B_col2

Table C
C_ID Primary Key
C_col1 (FK references either A_ID or B_ID)
C_col2


How do we deplict this relationship in Hibermate ?

In by hbm files

A.hbm
<one-to-one name="a" class="A" cascade="all" property-ref="aProp" constrained="false"/>
B.hbm
<one-to-one name="b" class="B" cascade="all" property-ref="bProp" constrained="false"/>
C.hbm
<many-to-one name="aProp" class="A" column="COL_A" unique="true" insert="false" update="false" />
<many-to-one name="bProp" class="B" column="COL_B" unique="true" not-null="false" />


When i try to save A/B separately, I get an error saying FK constraint violated. Say if i try to save A, attaching C to A,
It throws an exception as C expects B, which i dont want.
How to acehive this?
I gave insert="false" update="false" because, i got an error saying, if i use more than one many-to-one on tha same column, i have to specify one as insert="false" update="false"
That is the reason i gave that.
My objective is to save A with C set (or) B with C set to it

Can this be acheived somehow?

Can any of you please clarify this ???