PL/SQL: converting VARCHAR2 version of a geometry into an mdsys.sdo_geometr

Question

I'm writing some PL/SQL to parse through complex polygons and create new simple ones out of them. i.e. If i Have a multipolygon that contains 5 polygons, I want to produce 5 new polygons out of it. I'm generating the geometry as a varchar2 as I have some concatentaion to do and follow some logic.
Once I have this geometry created as a varchar2 how can i insert this as a geometry?
The following insert in PL/SQL
     insert into new_linestrings (id,geom,orig_id) values (se_new_linestrings.nextval,generated_geom,orig_id);
where generated_geom is a varchar2 generates the following error
26/2 PL/SQL: SQL Statement ignored
26/83 PL/SQL: ORA-00932: inconsistent datatypes: expected UDT got CHAR
And when I cast the varchar2 as a geometry like the following
     insert into new_linestrings (id,geom,orig_id) values (se_new_linestrings.nextval,cast (generated_geom as mdsys.sdo_geometry),orig_id);
I get the following error
ORA-00932: inconsistent datatypes: expected - got CHAR
ORA-06512: at "IVV.CREATE_GEOM", line 26
ORA-06512: at "IVV.CONVERT_TO_SIMPLE_LINES", line 26
ORA-06512: at line 1
How can i create a new geometry passing in a varchar2 in the constructor?
Thanks
Paul

Answer 1

You can do this by creating a string which is the full sql statement
and the executing it in PL/SQL.
For example, you have str1 := 'SDO_GEOMETRY(2006, 600000, NULL, SDO_ELEM_INFO_ARRAY(1, 2, 1, 13, 2, 1), SDO_ORDINATE_ARRAY(196741, 219623, 196743, 219623, 196745, 219623, 196746, 219637, 196742, 219639, 196741, 219623, 196746, 219637, 196746, 219637, 196746, 219637, 196746, 219637)) ';
Then make a SQL statement like this:
str2 := 'INSERT INTO new_linestrings (id,geom,orig_id) values ' || '('|| to_char(se_new_linestrings.nextval)|| ', ' ||str1|| ', ' ||to_char(orig_id) ') ';
execute immediate str2;
====
you may have to read in se_new_linestrings.nextval to a local variable
first.
siva