Hi Deepak,
CASE2 is wrong way.
You have two options.
1) many-to-many join table. This is the default.
2) foreign key column in ITEM. This is the result of inverse keyword.
Alternative 2 is more efficient, but it introduces a dependency at the db level from item to inventory, which is sometimes unwanted, especially when inventory and item are in different modules.
I don't think you can design this in the database in any other way.
Below INVENTORY table will not be able reference several items for one inventory.
CREATE TABLE INVENTORY (
INVENTORY_ID NUMBER(20) NOT NULL,
ITEM_ID NUMBER(20) NOT NULL,
)
/Patrik
deepshar027 wrote:
Hey Patrick,
I am facing this problem.
Consider this..similar like your example.
Entity Inventory{
- List<@Item> items
}
Entity Item{
}
This generates an additional table INVENTORY_ITEM which I dont want (many-2-many relationship.)
I want to have unidiretional relationship(one-2-many) as only inventory can have items.
Now If I do the following
CASE:1
Entity Inventory{
- List<@Item> items inverse
}
I see a reference of INVENTORY in item table which is not expected.
CREATE TABLE ITEM (
ITEM_ID NUMBER(20) NOT NULL,
INVENTORY NUMBER(20) ,
);
What I want to have is just below and there should no reference of Inventory in Item table.
CREATE TABLE INVENTORY (
INVENTORY_ID NUMBER(20) NOT NULL,
ITEM_ID NUMBER(20) NOT NULL,
)
CASE 2:
I did the following(Not sure why but I read somewhere that inverse creates a reference in the child table)
As such the following doesnt look correct to me but still I tried
Entity Inventory{
}
Entity Item{
- List<@Inventory> inv inverse
}
It does this which seems okk...although it creates this INV_INDEX(INTEGER) which I'll have to fix somehow to make NUMBER
CREATE TABLE INVENTORY (
INVENTORY_ID NUMBER(20) NOT NULL,
INV_INDEX INTEGER(10),
ITEM NUMBER(20)
);
This is fine so far....but in Item.hbm.xml I see
<list name="inv">
<key column="ITEM"/>
<index column="INV_INDEX"/>
<one-to-many class="com.bookonz.inventory.domain.Inventory"/>
</list>
I am not sure if this is correct? Should Item.hbm hold a reference to Inventory?
Please provide your inputs on this.
Thanks,
Deepak.
