8.51. determineattkindunique(p_idx_name text, p_tab_fqname name)

Function Properties

Language: PLPGSQL

Return Type: text

determineAttKindUnique (tab_fqname, indexname) Given a tablename, return the Slony-I specific attkind (used for the log trigger) of the table. Use the specified unique index or the primary key (if indexname is NULL).

declare
	v_tab_fqname_quoted	text default '';
	v_idx_name_quoted	text;
	v_idxrow		record;
	v_attrow		record;
	v_i				integer;
	v_attno			int2;
	v_attkind		text default '';
	v_attfound		bool;
begin
	v_tab_fqname_quoted := slon_quote_input(p_tab_fqname);
	v_idx_name_quoted := slon_quote_brute(p_idx_name);
	--
	-- 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: 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
		raise exception 'Slony-I: index name must be specified';
	else
		select PGXC.relname, PGX.indexrelid, PGX.indkey
				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) = v_idx_name_quoted;
		if not found then
			raise exception 'Slony-I: table % has no unique index %',
					v_tab_fqname_quoted, v_idx_name_quoted;
		end if;
	end if;

	--
	-- Loop over the tables attributes and check if they are
	-- index attributes. If so, add a "k" to the return value,
	-- otherwise add a "v".
	--
	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
		v_attfound = 'f';

		v_i := 0;
		loop
			select indkey[v_i] into v_attno from "pg_catalog".pg_index
					where indexrelid = v_idxrow.indexrelid;
			if v_attno isnull or v_attno = 0 then
				exit;
			end if;
			if v_attrow.attnum = v_attno then
				v_attfound = 't';
				exit;
			end if;
			v_i := v_i + 1;
		end loop;

		if v_attfound then
			v_attkind := v_attkind || 'k';
		else
			v_attkind := v_attkind || 'v';
		end if;
	end loop;

	-- Strip off trailing v characters as they are not needed by the logtrigger
	v_attkind := pg_catalog.rtrim(v_attkind, 'v');

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