Would it be faster to use a trigger or modify the insert query?

Question

We have a table that currently has latitude, longitude columns and are trying to decide what route to go as far as adding spatial data to future records. A spatial index will be placed on the new column.
There appear to be 3 solutions:
1 Create a materialized view which creates the spatial column based on the current latitude and longitude columns.
2 Create a trigger on the table that will populate the new spatial column on insert/update.
3 Modify the code to insert a spatial value into the new spatial column.
Due to the nature of the data we are not willing to use method 1.
What we are trying to figure out is which method, 2 or 3, will insert faster.
Has anyone done tests to determine if an insert with a spatial object is slower than an insert on a table with a trigger that creates a spatial object?
Thanks,
Pat

Answer 1

Pat,
Note that you don't need to store latitude, longitude in sdo_geometry type in order to spatially index it. Instead you can create a function that returns an sdo_geometry based on two numeric columns, then create a function based index on that. Its described here:
http://download.oracle.com/docs/cd/E11882_01/appdev.112/e11830/sdo_exten.htm#i1005799
Also note that in the sdo_geometry type, you need to define the data as longitude/latitude and not the other way around.
If you do want to create a column with sdo_geometry column, I'd recommend your third option. As a general principle I avoid triggers unless absolutely necessary. Triggers invariably lead to confusion when you (or someone else) revisits this code in the future. Also the change of context between and SQL and PL/SQL has a performance hit. Here's a simple test:
SQL> CREATE TABLE long_lat_no_trigger (
  2     geometry                SDO_GEOMETRY);
Table created.
SQL>
SQL> CREATE TABLE long_lat_with_trigger (
  2     longitude               NUMBER,
  3     latitude                NUMBER,
  4     geometry                SDO_GEOMETRY);
Table created.
SQL>
SQL> CREATE OR REPLACE TRIGGER long_lat_to_geometry
  2  BEFORE INSERT ON long_lat_with_trigger FOR EACH ROW
  3  DECLARE
  4  BEGIN
  5     :new.geometry := SDO_GEOMETRY(2001, 8307, SDO_POINT_TYPE(
  6     :new.longitude, :new.latitude, NULL), NULL, NULL);
  7  END;
  8  /
Trigger created.
SQL>
SQL> SET TIMING ON
SQL> INSERT INTO long_lat_no_trigger (geometry) (
  2     SELECT
  3     SDO_GEOMETRY(2001, 8307, SDO_POINT_TYPE(
  4     dbms_random.value(0,180), dbms_random.value(0,90),
  5     NULL), NULL, NULL)
  6     FROM DUAL
  7     CONNECT BY LEVEL <= 1000000);
1000000 rows created.
Elapsed: 00:00:31.96
SQL>
SQL> INSERT INTO long_lat_with_trigger (longitude, latitude) (
  2     SELECT
  3     dbms_random.value(0,180),
  4     dbms_random.value(0,90)
  5     FROM DUAL
  6     CONNECT BY LEVEL <= 1000000);
1000000 rows created.
Elapsed: 00:01:21.15Cheers,
John