improve function definitions; provide new function get_value()

examples/cities/pgsql/init_cities.sql

@@ -1,10 +1,10 @@
 
 create table cities (
-    rectype int,
-    ctype int,
+    rectype int not null,
+    ctype int not null,
     regiokey text not null primary key,
     ckey text not null,
-    name text,
+    name text not null,
     area decimal,
     inhabitants int,
     zipcode text,

pgsql/fload.sql

@@ -0,0 +1,35 @@
+
+create or replace function get_value(tname text, vtext text) returns bigint as $$
+begin
+  case tname
+    when 'node' then
+      return get_node(vtext);
+    when 'int' then
+      return to_number(vtext, '99999999');
+    else
+      return 0;
+  end case;
+end;
+$$ language plpgsql;
+
+
+create or replace function get_node(vtext text) returns bigint as $$
+declare
+  pfx text;
+  vname text;
+  value bigint;
+begin
+  pfx := split_part(vtext, ':', 1);
+  vname := split_part(vtext, ':', 2);
+  select nodes.id into value from nodes, namespaces ns
+    where ns.prefix = pfx
+      and nodes.namespace = ns.id
+      and nodes.name = vname;
+  if value is null then 
+      insert into nodes (namespace, name)
+        (select ns.id, vname from namespaces ns where ns.prefix = pfx)
+        returning nodes.id into value;
+  end if;
+  return value;
+end;
+$$ language plpgsql;

pgsql/fshow.sql

@@ -1,16 +1,22 @@
 
-create or replace function show(type smallint, id bigint) returns text as $$
+create or replace function show_value(type smallint, id bigint) returns text as $$
 declare tname text := (select dtname from datatypes as dt where dt.id = type);
 begin
-    case tname
-        when 'node' then
-            return (
-                select ns.prefix || ':' || n.name 
-                    from nodes n
-                    join namespaces ns on ns.id = n.namespace
-                    where n.id = show.id
-            );
-        else return tname;
-    end case;
+  return show_value(tname, id);
+end;
+$$ language plpgsql;
+
+create or replace function show_value(tname text, id bigint) returns text as $$
+begin
+  case tname
+    when 'node' then
+      return (
+        select ns.prefix || ':' || n.name 
+          from nodes n
+          join namespaces ns on ns.id = n.namespace
+          where n.id = show_value.id
+      );
+    else return text(show_value.id);
+  end case;
 end;
 $$ language plpgsql;

pgsql/init.sql

@@ -64,7 +64,7 @@ INSERT INTO datatypes (dtname, tablename) VALUES
     ('triple', 'triples'),          -- 5
     ('text', 'texts');              -- 6
 INSERT INTO datatypes (dtname) VALUES 
-    ('int'), ('float'), ('decimal'), ('timestamp'); -- 7, 8, 9, 10
+    ('int'), ('decimal'), ('timestamp'); -- 7, 8, 9
 
 INSERT INTO nodes (namespace, name) VALUES 
     (2, 'type'),        -- 1

pgsql/vtriples.sql

@@ -1,9 +1,9 @@
 
 create or replace view vtriples as
 select triples.id,
-       stype, svalue, show(stype, svalue) as stext, 
-       predicate, show(dt.id, predicate) as ptext, 
-       otype, ovalue, show(otype, ovalue) as otext,
+       stype, svalue, show_value(stype, svalue) as stext, 
+       predicate, show_value(dt.id, predicate) as ptext, 
+       otype, ovalue, show_value(otype, ovalue) as otext,
        events.tstamp as ts
   from triples, datatypes dt, events
   where dtname = 'node'