Overview

When you use CREATE INDEX to create an index or ALTER INDEX to manage an index, you can optionally specify indexing preferences, stoplists, and section groups in the parameter string. Specifying a preference, stoplist, or section group answers one of the following questions about the way Oracle indexes text:

Preference Class	Answers the Question
Datastore	How are your documents stored?
Filter	How can the documents be converted to plain text?
Lexer	What language is being indexed?
Wordlist	How should stem and fuzzy queries be expanded?
Storage	How should the index tables be stored?
Stop List	What words or themes are not to be indexed?
Section Group	Is querying within sections enabled, and how are the document sections defined?

This chapter describes how to set each preference. You enable an option by creating a preference with one of the types described in this chapter.

For example, to specify that your documents are stored in external files, you can create a datastore preference called mydatastore using the FILE_DATASTORE type. You specify mydatastore as the datastore preference in the parameter clause of CREATE INDEX.

Creating Preferences

To create a datastore, lexer, filter, wordlist, or storage preference, you use the CTX_DDL.CREATE_PREFERENCE procedure and specify one of the types described in this chapter. For some types, you can also set attributes with the CTX_DDL.SET_ATTRIBUTE procedure.

To create a stoplists, use CTX_DDL.CREATE_STOPLIST. You can add stopwords to a stoplist with CTX_DDL.ADD_STOPWORD.

To create section groups, use CTX_DDL.CREATE_SECTION_GROUP and specify a section group type. You can add sections to section groups with CTX_DDL. ADD_ZONE_SECTION or CTX_DDL.ADD_FIELD_SECTION.