=?iso-8859-1?Q?Egy=FCd_Csaba?= <csegyud@vnet.hu> writes:
> I've got it, but I don't know the reason of it.
> In the database table the records have duplicated and I've two rows for
> every primary key - with different OIDs.
Sure sounds like a child table to me.
> Is there any safe method to get rid of only one of each duplicated row?
Drop the child table.
regards, tom lane