Oracle Text: CTXCAT

Question

Hi all, I have the following table
CREATE TABLE SEM_TRAJS OF SEM_TRAJECTORY
NESTED TABLE EPISODES STORE AS EPISODES_NESTEDTAB ...
and the following types
CREATE OR REPLACE
type SEM_TRAJECTORY as object
-- Attributes
sem_trajectory_tag varchar2(50),
srid integer,
episodes sem_episode_tab,
o_id integer,
semtraj_id integer,
and CREATE OR REPLACE
type EPISODE as object
-- Attributes
defining_tag varchar2(4),
episode_tag varchar2(50),
activity_tag varchar2(50),
Now i want to create a pattern matching query with Oracle Text so I can search in defining_tag, episode_tag, activity_tag ... How can I create a CTXCAT index and use it?
Thanks in advance.

Answer 1

You won't be able to create a Text index (ctxcat or context) on an object table directly, so I would create a materialized view, then create the index on the materialized view. The following is a fairly simple example, using a materialized view, a multi_column_datastore, and a context index. You could use a user_datastore with a procedure instead of the multi_column_datastore, but that would be a bit more complicated. You will need to deal with refreshing your materialized view and synchronizing your index and you could add sections if you want to search within individual attributes of the episodes. This is just a simple starter example. It looks like your problem is an interesting combination of Text, Objects, and Spatial. The data that I used is just for the simple demonstration and is not valid spatial data.
SCOTT@orcl_11gR2> CREATE OR REPLACE TYPE episode AS OBJECT
  2    (defining_tag  VARCHAR2( 4),
  3       episode_tag   VARCHAR2(50),
  4       activity_tag  VARCHAR2(50));
  5  /
Type created.
SCOTT@orcl_11gR2> CREATE OR REPLACE TYPE sem_episode_tab AS TABLE OF episode
  2  /
Type created.
SCOTT@orcl_11gR2> CREATE OR REPLACE TYPE sem_trajectory AS OBJECT
  2    (sem_trajectory_tag  VARCHAR2(50),
  3       srid              INTEGER,
  4       episodes         sem_episode_tab,
  5       o_id              INTEGER,
  6       semtraj_id         INTEGER)
  7  /
Type created.
SCOTT@orcl_11gR2> SHOW ERRORS
No errors.
SCOTT@orcl_11gR2> CREATE TABLE sem_trajs OF sem_trajectory
  2  NESTED TABLE episodes STORE AS episodes_nestedtab
  3  /
Table created.
SCOTT@orcl_11gR2> INSERT INTO sem_trajs
  2  VALUES
  3    ('semtrajtag1',
  4       1,
  5       sem_episode_tab
  6         (episode ('dt1a', 'etag1a', 'atag1a'),
  7          episode ('dt1b', 'etag1b', 'atag1b')),
  8       1,
  9       1)
10  /
1 row created.
SCOTT@orcl_11gR2> INSERT INTO sem_trajs
  2  VALUES
  3    ('semtrajtag2',
  4       2,
  5       sem_episode_tab
  6         (episode ('dt2a', 'etag2a', 'atag2a'),
  7          episode ('dt2b', 'etag2b', 'atag2b')),
  8       2,
  9       2)
10  /
1 row created.
SCOTT@orcl_11gR2> CREATE MATERIALIZED VIEW episodes_mv
  2  AS
  3  SELECT st.sem_trajectory_tag, st.srid, st.o_id, semtraj_id,
  4           e.defining_tag, e.episode_tag, e.activity_tag,
  5           ' ' AS episodes
  6  FROM   sem_trajs st,
  7           TABLE (st.episodes) e
  8  /
Materialized view created.
SCOTT@orcl_11gR2> COLUMN sem_trajectory_tag FORMAT A18
SCOTT@orcl_11gR2> COLUMN defining_tag         FORMAT A12
SCOTT@orcl_11gR2> COLUMN episode_tag         FORMAT A11
SCOTT@orcl_11gR2> COLUMN activity_tag         FORMAT A12
SCOTT@orcl_11gR2> SELECT * FROM episodes_mv
  2  /
SEM_TRAJECTORY_TAG       SRID       O_ID SEMTRAJ_ID DEFINING_TAG EPISODE_TAG ACTIVITY_TAG E
semtrajtag1                 1          1          1 dt1a         etag1a      atag1a
semtrajtag1                 1          1          1 dt1b         etag1b      atag1b
semtrajtag2                 2          2          2 dt2a         etag2a      atag2a
semtrajtag2                 2          2          2 dt2b         etag2b      atag2b
4 rows selected.
SCOTT@orcl_11gR2> BEGIN
  2    CTX_DDL.CREATE_PREFERENCE ('emv_mcds', 'MULTI_COLUMN_DATASTORE');
  3    CTX_DDL.SET_ATTRIBUTE ('emv_mcds', 'COLUMNS', 'defining_tag, episode_tag, activity_tag');
  4  END;
  5  /
PL/SQL procedure successfully completed.
SCOTT@orcl_11gR2> CREATE INDEX indexname
  2    ON episodes_mv (episodes)
  3    INDEXTYPE IS CTXSYS.CONTEXT
  4    PARAMETERS ('DATASTORE emv_mcds')
  5  /
Index created.
SCOTT@orcl_11gR2> SELECT * FROM episodes_mv
  2  WHERE  CONTAINS (episodes, 'dt1a') > 0
  3  /
SEM_TRAJECTORY_TAG       SRID       O_ID SEMTRAJ_ID DEFINING_TAG EPISODE_TAG ACTIVITY_TAG E
semtrajtag1                 1          1          1 dt1a         etag1a      atag1a
1 row selected.
SCOTT@orcl_11gR2> SELECT * FROM episodes_mv
  2  WHERE  CONTAINS (episodes, 'atag2b') > 0
  3  /
SEM_TRAJECTORY_TAG       SRID       O_ID SEMTRAJ_ID DEFINING_TAG EPISODE_TAG ACTIVITY_TAG E
semtrajtag2                 2          2          2 dt2b         etag2b      atag2b
1 row selected.