one column forming uniqueness with multiple different cols

hariprasad · **Joined:** Tue Jun 17, 2008 12:35 am **Posts:** 2

I have a requirement like where one column forms uniqueness with multiple different columns. For example consider columns A, B and C where A+B should be unique also A+C should be unique. I can't use unique-key or natural-id because they form uniqueness with whole combination i.e, A+B+C. At data base level I can specify A+B and A+C are unique. Could anybody please tell how to keep this constraint in hibernate mapping file.

Thanks,
Hari Prasad Alla

Cameron McKenzie · **Posted:** Tue Jun 17, 2008 4:02 pm

So, you're saying that using compound primary keys, even in combination, simply isn't a feasable option?

ramnath · **Posted:** Wed Jun 18, 2008 10:23 am

I have not heard about multiple composite-id in one mapping...Wait for others reply...I'm in interested to hear more on this??

workaround: Give it a try..
You will be implementing the equals() and hashCode() to achieve the unqiueness...So write these checking in the above mehtods for your requirments..Hibernate will not error ....Only proper implementation of these methods will prevent duplication of composite PK's.

hariprasad · **Joined:** Tue Jun 17, 2008 12:35 am **Posts:** 2

My mapping does not worry about defining PK or composite PK.

Code:

<hibernate-mapping>
 <class entity-name="ITEM_ITEM_PC" table="ITEM_ITEM_PC">
   <id name="ID" type="long" column="ID" unsaved-value="0">
   <generator class="sequence">
   <param name="sequence">dyn_seq_28</param>
   </generator>
   </id>   
   <property name="USER_DOC_ID" type="string" column="USER_DOC_ID" not-null="true" unique-key="composite_unique" />
   <property name="IS_ACTIVE" type="boolean" column="IS_ACTIVE" not-null="true" />
   <property name="rtd_version" type="integer" column="rtd_version" not-null="true" unique-key="composite_unique" />
   <property name="TEMPLATE_NAME" column="TEMPLATE_NAME" type="string" />   
   <property name="ORDINAL" type="integer" column="ORDINAL" not-null="false" />   
   <property name="lineId" type="string" column="lineId" not-null="false" length="32" unique-key="composite_unique" />   
</class>
</hibernate-mapping>

In above mapping i have defined unique-key for "USER_DOC_ID", "rtd_version" and "lineId" which makes combination("USER_DOC_ID" + "rtd_version" + "lineId") unique. But i want uniqueness on ("USER_DOC_ID" + "rtd_version") and ("USER_DOC_ID" + "lineId").

my table script is,

Code:

CREATE TABLE  "ITEM_ITEM_PC" 
   (   "ID" NUMBER(19,0) NOT NULL ENABLE, 
   "TEMPLATE_NAME" VARCHAR2(255 CHAR) NOT NULL ENABLE,   
   "USER_DOC_ID" VARCHAR2(255 CHAR) NOT NULL ENABLE, 
   "IS_ACTIVE" NUMBER(1,0) NOT NULL ENABLE,   
   "RTD_VERSION" NUMBER(10,0) NOT NULL ENABLE,   
   "ORDINAL" NUMBER(10,0),     
   "LINEID" VARCHAR2(32 CHAR),     
    PRIMARY KEY ("ID") ENABLE, 
    UNIQUE ("USER_DOC_ID", "RTD_VERSION", "LINEID") ENABLE,
   )

And i can modify the constraint in script like UNIQUE ("USER_DOC_ID", "RTD_VERSION")
UNIQUE ("USER_DOC_ID", "LINEID")
to make ("USER_DOC_ID" + "rtd_version") and ("USER_DOC_ID" + "lineId") unique.
.

So i want to define same constraint at hbm level. I hope the problem is clear.

Thanks,
Hari Prasad Alla.