Si la table n'a pas obtenu une colonne de la forme _Slony-I_<clustername>_rowID, alors l'ajoute avec le type bigint et comme valeur par défaut le nextval() d'une séquence créée pour le cluster.

declare
        p_tab_fqname    alias for $1;
        v_tab_fqname_quoted     text default '';
        v_attkind               text default '';
        v_attrow                record;
        v_have_serial   bool default 'f';
begin
        v_tab_fqname_quoted := slon_quote_input(p_tab_fqname);
        --
        -- Loop over the attributes of this relation
        -- and add a "v" for every user column, and a "k"
        -- if we find the Slony-I special serial column.
        --
        for v_attrow in select PGA.attnum, PGA.attname
                        from "pg_catalog".pg_class PGC,
                            "pg_catalog".pg_namespace PGN,
                                "pg_catalog".pg_attribute PGA
                        where slon_quote_brute(PGN.nspname) || '.' ||
                            slon_quote_brute(PGC.relname) = v_tab_fqname_quoted
                                and PGN.oid = PGC.relnamespace
                                and PGA.attrelid = PGC.oid
                                and not PGA.attisdropped
                                and PGA.attnum > 0
                        order by attnum
        loop
                if v_attrow.attname = '_Slony-I_schemadoc_rowID' then
                    v_attkind := v_attkind || 'k';
                        v_have_serial := 't';
                else
                        v_attkind := v_attkind || 'v';
                end if;
        end loop;
        
        --
        -- A table must have at least one attribute, so not finding
        -- anything means the table does not exist.
        --
        if not found then
                raise exception 'Slony-I: tableAddKey(): table % not found', v_tab_fqname_quoted;
        end if;

        --
        -- If it does not have the special serial column, we
        -- have to add it. This will be only half way done.
        -- The function to add the table to the set must finish
        -- these definitions with NOT NULL and UNIQUE after
        -- updating all existing rows.
        --
        if not v_have_serial then
                execute 'lock table ' || v_tab_fqname_quoted ||
                        ' in access exclusive mode';
                execute 'alter table only ' || v_tab_fqname_quoted ||
                        ' add column "_Slony-I_schemadoc_rowID" bigint;';
                execute 'alter table only ' || v_tab_fqname_quoted ||
                        ' alter column "_Slony-I_schemadoc_rowID" ' ||
                        ' set default "pg_catalog".nextval(''sl_rowid_seq'');';

                v_attkind := v_attkind || 'k';
        end if;

        --
        -- Return the resulting Slony-I attkind
        --
        return v_attkind;
end;