About the Text Index

In pre-8.1, the index is created with the CTX_DDL package by first creating a policy and then using the policy to create the index.

In 8.1, a Text index is created as a special type of extensible index to Oracle using standard SQL. This means that a interMedia Text 8.1 index operates like an Oracle index. It has a name by which it is referenced, and policies do not exist.

See Also: For more information about creating a Text index, see "Procedure for Creating Index" in this chapter.

Merged Word and Theme Index (English only)

In 8.1, a single text index can contain both theme and word information. This is different from pre-8.1 where you needed a theme index in addition to a text index to issue theme queries.

By default in English, interMedia Text indexes theme information with word information. You can optionally enable and disable theme indexing with your lexer preference.

See Also: To learn more about indexing theme information, see "Creating Preferences" in this chapter.

Columns with Multiple Indexes

In pre-8.1, the system allows you to create more than one index on a text column. This is useful when you want a text column to have a text and theme index.

In 8.1, a column can have no more than a single domain index attached to it, which is in keeping with Oracle standards. However, a single Text index can contain theme information in addition to word information.

Indexing Views

In pre-8.1, you can create a ConText index on a view. This might be useful when you need to index documents whose content is pieced together from different tables.

However, Oracle SQL standards does not support creating indexes on views. Therefore in 8.1, if you need to create and index documents whose contents are in different tables, you can create a data storage preference using the USER_DATSTORE object, which is new for 8.1. With this object, you can define a procedure that synthesizes documents at index time.

See Also: To learn more about USER_DATASTORE, see Oracle8i interMedia Text Reference.