Obtaining info on UNIQUE constratints.

[Tim Dudgeon <td...@informaticsmatters.com>]

How do you find out which UNIQUE constraints exist for a table, and 
which columns they use?
DatabaseMetaData.getIndexInfo( ... ) can give me the information about 
the indexes, but it seems that in Derby a UNIQUE index is not the same 
thing as a UNIQUE constraint.

Thanks

Tim

Re: Obtaining info on UNIQUE constratints.

[Tim Dudgeon <td...@informaticsmatters.com>]

Rick Hillegas wrote:
> Tim Dudgeon wrote:
>> How do you find out which UNIQUE constraints exist for a table, and 
>> which columns they use?
>> DatabaseMetaData.getIndexInfo( ... ) can give me the information about 
>> the indexes, but it seems that in Derby a UNIQUE index is not the same 
>> thing as a UNIQUE constraint.
>>
>> Thanks
>>
>> Tim
>>
> Hi Tim,
> 
> 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:
> 
> select g.descriptor
> from sys.systables t, sys.sysconstraints c, sys.syskeys k, 
> sys.sysconglomerates g
> where t.tablename = 'FOO'
> and t.tableid = c.tableid
> and c.type = 'U'
> and c.constraintid = k.constraintid
> and k.conglomerateid = g.conglomerateid
> ;
> 
> Hope this helps,
> -Rick
> 
> 
Thanks. That helped.

Tim

Re: Obtaining info on UNIQUE constratints.

[Rick Hillegas <Ri...@Sun.COM>]

Tim Dudgeon wrote:
> How do you find out which UNIQUE constraints exist for a table, and 
> which columns they use?
> DatabaseMetaData.getIndexInfo( ... ) can give me the information about 
> the indexes, but it seems that in Derby a UNIQUE index is not the same 
> thing as a UNIQUE constraint.
>
> Thanks
>
> Tim
>
Hi Tim,

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:

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

Hope this helps,
-Rick