CREATE_POLICY

Creates a policy to use with the CTX_DOC.POLICY_* procedures and the ORA:CONTAINS function. ORA:CONTAINS is a function you use within an XPATH query expression with existsNode().

See Also: Oracle XML DB Developer’s Guide

Syntax

CTX_DDL.CREATE_POLICY(
         policy_name     IN VARCHAR2,
         filter          IN VARCHAR2 DEFAULT NULL,
         section_group   IN VARCHAR2 DEFAULT NULL,
         lexer           IN VARCHAR2 DEFAULT NULL,
         stoplist        IN VARCHAR2 DEFAULT NULL,
         wordlist        IN VARCHAR2 DEFAULT NULL);

policy_name

Specify the name for the new policy. Policy names and Text indexes share the same namespace.

filter

Specify the filter preference to use.

section_group

Specify the section group to use. You can specify any section group that is supported by CONTEXT index.

lexer

Specify the lexer preference to use. Your INDEX_THEMES attribute must be disabled.

stoplist

Specify the stoplist to use.

wordlist

Specify the wordlist to use.

Example

Create mylex lexer preference named mylex.

begin
   ctx_ddl.create_preference('mylex', 'BASIC_LEXER');
   ctx_ddl.set_attribute('mylex', 'printjoins', '_-');
   ctx_ddl.set_attribute ( 'mylex', 'index_themes', 'NO');
   ctx_ddl.set_attribute ( 'mylex', 'index_text', 'YES');
end;

Create a stoplist preference named mystop.

begin
  ctx_ddl.create_stoplist('mystop', 'BASIC_STOPLIST');
  ctx_ddl.add_stopword('mystop', 'because');
  ctx_ddl.add_stopword('mystop', 'nonetheless');
  ctx_ddl.add_stopword('mystop', 'therefore');
end;

Create a wordlist preference named ‘mywordlist’.

begin
 ctx_ddl.create_preference('mywordlist', 'BASIC_WORDLIST');
 ctx_ddl.set_attribute('mywordlist','FUZZY_MATCH','ENGLISH');
 ctx_ddl.set_attribute('mywordlist','FUZZY_SCORE','1');
 ctx_ddl.set_attribute('mywordlist','FUZZY_NUMRESULTS','5000');
 ctx_ddl.set_attribute('mywordlist','SUBSTRING_INDEX','TRUE');
 ctx_ddl.set_attribute('mywordlist','STEMMER','ENGLISH');
end;

exec ctx_ddl.create_policy('my_policy', NULL, NULL, 'mylex', 'mystop',
'mywordlist');

or

exec ctx_ddl.create_policy(policy_name => 'my_policy',
                           lexer => 'mylex',
                           stoplist => 'mystop',
                           wordlist => 'mywordlist');

Then enter the following existsNode() query with your own defined policy:

select id from xmltab
  where existsNode(doc, '/book/chapter[ ora:contains(summary,"dog or cat",
  "my_policy") >0 ]', 'xmlns:ora="http://xmlns.example.com/xdb" ')=1;

Update the policy with the following:

exec ctx_ddl.update_policy(policy_name => 'my_policy', lexer => 'my_new_lex');

Drop the policy with the following:

exec ctx_ddl.drop_policy(policy_name => 'my_policy');