It’s not easy to get information on derby keys once you created them. I was looking for a command like “SHOW CREATE TABLE ” but no luck. I realized that the answer should lay in SYS tables. After googling a while I found the following bit of wisdom:

The following query will give you the UNIQUE constraints on a table:

select c.constraintname, c.constraintid
from sys.systables t, sys.sysconstraints c
where t.tablename = ‘FOO’
and t.tableid = c.tableid
and c.type = ‘U’;

The following query will return a descriptor object for each constraint
on the table. The descriptor will tell you which columns are in each
constraint. As noted in the Reference Guide section on
SYS.SYSCONGLOMERATES, the descriptor object implements
org.apache.derby.catalog.IndexDescriptor. Please note that the
descriptor object is not part of Derby’ public API and can therefore
change from release to release:

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<span class='line'>select g.descriptor
</span><span class='line'>from sys.systables t, sys.sysconstraints c, sys.syskeys k,
</span><span class='line'>sys.sysconglomerates g
</span><span class='line'>where t.tablename = 'FOO'
</span><span class='line'>and t.tableid = c.tableid
</span><span class='line'>and c.type = 'U'
</span><span class='line'>and c.constraintid = k.constraintid
</span><span class='line'>and k.conglomerateid = g.conglomerateid;</span>



  


  

    
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