stored procedures: sybase -> postgreSQL ?

I am trying to port a Sybase table create script to one usable for
postgreSQL.

(note I am not a DBA)

In particular I am not well versed on how to use/recode the stored
procedures such as that in the example below.

ALTER TABLE DnaFragment
ADD PRIMARY KEY (dna_fragment_id)
go

exec sp_primarykey DnaFragment,
dna_fragment_id
go

exec sp_bindrule DnaFragment_type_rule, 'DnaFragment.type'
exec sp_bindefault Set_To_Current_Date,
'DnaFragment.date_last_modified'
exec sp_bindefault Set_to_False, 'DnaFragment.is_obsolete'
go

regards,

Charles