FUNCTION determineIdxnameUnique (tab_fqname, indexname) Suivant un nom de table, tab_fqname, vérifie que l'index unique, indexname, existe ou renvoie le nom de l'index de clé primaire pour la table. S'il n'y a pas d'index unique, il lève une exception.

declare
        p_tab_fqname    alias for $1;
        v_tab_fqname_quoted     text default '';
        p_idx_name              alias for $2;
        v_idxrow                record;
begin
        v_tab_fqname_quoted := slon_quote_input(p_tab_fqname);
        --
        -- Ensure that the table exists
        --
        if (select PGC.relname
                                from "pg_catalog".pg_class PGC,
                                        "pg_catalog".pg_namespace PGN
                                where slon_quote_brute(PGN.nspname) || '.' ||
                                        slon_quote_brute(PGC.relname) = v_tab_fqname_quoted
                                        and PGN.oid = PGC.relnamespace) is null then
                raise exception 'Slony-I: determineIdxnameUnique(): table % not found', v_tab_fqname_quoted;
        end if;

        --
        -- Lookup the tables primary key or the specified unique index
        --
        if p_idx_name isnull then
                select PGXC.relname
                                into v_idxrow
                                from "pg_catalog".pg_class PGC,
                                        "pg_catalog".pg_namespace PGN,
                                        "pg_catalog".pg_index PGX,
                                        "pg_catalog".pg_class PGXC
                                where slon_quote_brute(PGN.nspname) || '.' ||
                                        slon_quote_brute(PGC.relname) = v_tab_fqname_quoted
                                        and PGN.oid = PGC.relnamespace
                                        and PGX.indrelid = PGC.oid
                                        and PGX.indexrelid = PGXC.oid
                                        and PGX.indisprimary;
                if not found then
                        raise exception 'Slony-I: table % has no primary key',
                                        v_tab_fqname_quoted;
                end if;
        else
                select PGXC.relname
                                into v_idxrow
                                from "pg_catalog".pg_class PGC,
                                        "pg_catalog".pg_namespace PGN,
                                        "pg_catalog".pg_index PGX,
                                        "pg_catalog".pg_class PGXC
                                where slon_quote_brute(PGN.nspname) || '.' ||
                                        slon_quote_brute(PGC.relname) = v_tab_fqname_quoted
                                        and PGN.oid = PGC.relnamespace
                                        and PGX.indrelid = PGC.oid
                                        and PGX.indexrelid = PGXC.oid
                                        and PGX.indisunique
                                        and slon_quote_brute(PGXC.relname) = slon_quote_input(p_idx_name);
                if not found then
                        raise exception 'Slony-I: table % has no unique index %',
                                        v_tab_fqname_quoted, p_idx_name;
                end if;
        end if;

        --
        -- Return the found index name
        --
        return v_idxrow.relname;
end;