Stoplists

By default, the system indexes text using the system-supplied stoplist that corresponds to the language of your database setup. Stoplists identify the words in your language that are not to be indexed. In English, you can also identify stopthemes that are not to be indexed.

Oracle8i interMedia Text provides default stoplists for most languages including English, French, German, Spanish, Dutch, and Danish. These default stoplists contain only stopwords.

Creating Stoplists

You can create your own stoplists using CTX_DLL.CREATE_STOPLIST.

When you create your own stoplist, you must specify it in the parameter string of CREATE INDEX.

Modifying the Default Stoplist

The default stoplist is always named CTXSYS.DEFAULT_STOPLIST. You can use the following procedures to modify this stoplist:

• CTX_DDL.ADD_STOPWORD

• CTX_DDL.REMOVE_STOPWORD

• CTX_DDL.ADD_STOPTHEME

• CTX_DDL.ADD_STOPCLASS

When you modify CTXSYS.DEFAULT_STOPLIST with the CTX_DDL package, you must recreate your index for the changes to take effect.

Dynamic Addition of Stopwords

You can add stopwords dynamically to a stoplist, default or custom, with ALTER INDEX. When you add a stopword dynamically, you need not re-index since the word immediately becomes stopword and is removed from the index.

Note: Even though you can dynamically add stopwords to an index, you cannot dynamically remove stopwords. To remove a stopword, you must use CTX_DDL.REMOVE_STOPWORD and re-index.