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By default, Blueriq uses the CTX_SYS.DEFAULT_LEXER which comes pre-configured with various settings depending on the language used when the database was installed. For example, if the Oracle database was installed with the Dutch language, the default lexer has composite indexing and alternate spelling enabled for the Dutch language. If a custom lexer is defined, make sure not to omit any settings from the default lexer that you would like to keep.

Creating a case-insensitive lexer

To enable case-sensitivity, a custom lexer must be defined and configured:

Code Block
languagesql
begin
	ctx_ddl.create_preference('example_lexer', 'BASIC_LEXER');
	ctx_ddl.set_attribute('example_lexer', 'mixed_case', 'no'); -- no = case sensitive, yes = case insensitive
end;

Setting the lexer at index creation time

The custom lexer is specified as an index parameter:

Code Block
languagesql
drop index aq_fulltext_index;
create index aq_fulltext_index on aq_fulltext(text) 
  indextype is ctxsys.context 
  parameters ('datastore aq_fulltext_uds lexer example_lexer sync(every "sysdate+1/24")');

Changing the lexer without recreating the index

The lexer can also be changed without dropping the index first:

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