CTX_DDL Package, 11 of 24

CREATE_PREFERENCE

Creates a preference in the Text data dictionary. You specify preferences in the parameter string of CREATE INDEX or ALTER INDEX.

Syntax

CTX_DDL.CREATE_PREFERENCE(preference_name  in varchar2, 
                          object_name      in varchar2);

preference_name

Specify the name of the preference to be created.

object_name

Specify the name of the preference object.

See Also:
For a complete list of preference objects and their associated attributes, see Chapter 3, "Indexing".

Examples

Creating Text-only Index

The following example creates a lexer preference that specifies a text-only index. It does so by creating a BASIC_LEXER preference called my_lexer with CTX_DDL.CREATE_PREFERENCE. It then calls CTX_DDL.SET_ATTRIBUTE twice, first specifying Y for the INDEX_TEXT attribute, then specifying N for the INDEX_THEMES attribute.

begin
ctx_ddl.create_preference('my_lexer', 'BASIC_LEXER');
ctx_ddl.set_attribute('my_lexer', 'INDEX_TEXT', 'YES');
ctx_ddl.set_attribute('my_lexer', 'INDEX_THEMES', 'NO');
end;

Specifying File Data Storage

The following example creates a data storage preference called mypref that tells the system that the files to be indexed are stored in the operating system. The example then uses CTX_DDL.SET_ATTRIBUTE to set the PATH attribute of to the directory /docs.

begin
ctx_ddl.create_preference('mypref', 'FILE_DATASTORE');
ctx_ddl.set_attribute('mypref', 'PATH', '/docs'); 
end;

See Also:
For more information about data storage, see "Datastore Objects" in Chapter 3.

Creating Master/Detail Relationship

You use CTX_DDL.CREATE_PREFERENCE to create a preference with DETAIL_DATASTORE. You use CTX_DDL.SET_ATTRIBUTE to set the attributes for this preference. The following example shows how this is done:

begin
ctx_ddl.create_preference('my_detail_pref', 'DETAIL_DATASTORE');
ctx_ddl.set_attribute('my_detail_pref', 'binary', 'true');
ctx_ddl.set_attribute('my_detail_pref', 'detail_table', 'my_detail');
ctx_ddl.set_attribute('my_detail_pref', 'detail_key', 'article_id');
ctx_ddl.set_attribute('my_detail_pref', 'detail_lineno', 'seq');
ctx_ddl.set_attribute('my_detail_pref', 'detail_text', 'text');
end;

See Also:
For more information about master/detail, see "DETAIL_DATASTORE" in Chapter 3.

Specifying Storage Attributes

The following examples specify that the index tables are to be created in the foo tablespace with an initial extent of 1K:

begin
ctx_ddl.create_preference('mystore', 'BASIC_STORAGE');
ctx_ddl.set_attribute('mystore', 'I_TABLE_CLAUSE',
                        'tablespace foo storage (initial 1K)'); 
ctx_ddl.set_attribute('mystore', 'K_TABLE_CLAUSE',
                        'tablespace foo storage (initial 1K)'); 
ctx_ddl.set_attribute('mystore', 'R_TABLE_CLAUSE',
                        'tablespace foo storage (initial 1K)'); 
ctx_ddl.set_attribute('mystore', 'N_TABLE_CLAUSE',
                        'tablespace foo storage (initial 1K)'); 
ctx_ddl.set_attribute('mystore', 'I_INDEX_CLAUSE',
                        'tablespace foo storage (initial 1K)'); 
end;

See Also:
For more information about storage, see "Storage Objects" in Chapter 3.

Creating Preferences with No Attributes

When you create preferences with objects that have no attributes, you need only create the preference, as in the following example which sets the filter to the NULL_FILTER:

begin
ctx_ddl.create_preference('my_null_filter', 'NULL_FILTER');
end;