Oracle Database Discussions

Hi,

I am working on 11g and AIX...We got deadlock recently and we need to investgate why it happen and resolution, so it will not happen in future..
When we saw deadlock trace file ,it shows 2 sqls queries on different tables..and lock is execlusive lock.

----- Information for the OTHER waiting sessions -----

SELECT 1 FROM HOS_DTL WHERE ( HOS_LCN_DTL.HOS_LCN_DTL_ID = :1 ) FOR UPDATE WAIT 180

and

----- Current SQL Statement for this session ------

DELETE FROM EI_INV WHERE ( EI_INV.EI_INV_ID = :1 )


But these two tables not related at all 'HOS_DTL' and 'EI_INV' .
Can deadlock happen if sqls queries fired on those table are not related at all and deadlock
trace file can show those two sqls ..?

Any idea....