On Wed, 30 Jul 2014, Michael Bayer wrote:
Typically a UNIQUE constraint is placed on the "natural" key to prevent dupes.
I can see this when the natural key is a single column, but wonder how a compound natural key is represented if a serial integer is used as the surrogate 'id' key. For example, class Changed_Data(Base): __tablename__ = changed_data id = Column(Integer, primary_key = True) which_table = Column(unicode(32), nullable = False) which_attrib = Column(unicode(32), nullable = False) when_changed = Column(Timestamp, nullable = False) curr_value = Column(Unicode(32), nullable = False) new_value = Column(Unicode(32), nullable = False) changed_by = Column(Unicode(32), nullable = False) reason = Column(Text) The postgres schema specifies the primary key as (which_table, which_attribute, when_changed). If I make each of those columns Unique is it the set of columns that is unique or each individual column? TIA, Rich -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.