The SQL catalog VIEWs SYSCSTDEP and SYSCST should include the
constraints. The TABLE where the data comes from is the System Database
Cross-Reference file QADBFCST in QSYS; shown in the CREATE VIEW
statement text for those VIEWs.

A unique index, unless it is a SQL INDEX, does not appear in
SYSINDEXES. According to the CREATE VIEW statement text, the selection
from the System Database Cross-Reference file QADBXREF in QSYS has in
its WHERE clause: DBXATR = 'IX'

I infer from the scenario that there may be an intermixing of SQL and
DDS created logical files; that the unique logical file is DDS created,
rather than an SQL INDEX. To include both SQL and DDS created files in
a query of the database cross-reference, create a different VIEW to be
referenced [a VIEW which does not exclude non-SQL objects], query the
Database Cross-References files directly, or refer to the
self-describing information extracted from the objects themselves [e.g.
the DSPDBR and DSPFD; or equivalent APIs],

Regards, Chuck
--
All comments provided "as is" with no warranties of any kind
whatsoever and may not represent positions, strategies, nor views of my
employer

Pegaz wrote:
> I received SQL0803 message during update of table T. "Unique index
> or unique constraint exists". SYSCSTDEP and SYSINDEXES catalog views
> contain no information for constraint and index. However, using
> DSPDBR and DSPFD command, I found information about unique key
> values required for logical files related to table/file T.
>
> Which catalogs view contains information related to data presented
> by DSPFD for logical file ?