Supplied Stoplists
By default, the system indexes text using the Oracle Text supplied stoplists that correspond to your database language.
A stoplist is a list of stopwords that do not get indexed. These are usually common words in a language, such as this, that, and can in English. By default, all such words are defined in the Oracle Text supplied stoplists. You can customize these stoplists or update the stopwords based on your requirements.
Supported Languages and Stoplists Location
The Oracle Text supplied stoplists contain a list of stopwords, which are provided as defaults for all BASIC_LEXER and AUTO_LEXER supported languages. These stopwords are automatically loaded during installation or upgrade for the chosen database language.
The default stoplists (along with other default preferences) are defined in the administration (SQL) files, which are located in the $ORACLE_HOME/ctx/admin directory. These SQL files are named drdefLANG.sql, where LANG specifies the language code. For example, the default stoplist for French (language code: f) is defined in the $ORACLE_HOME/ctx/admin/drdeff.sql file.
The source files for these default stoplists contain a list of stopwords, and are located in the $ORACLE_HOME/ctx/data/stoplist directory. These source files are named drstopLANG.txt, where LANG specifies the language code. The contents of the source files are the extracted terms from the drdefLANG.sql files.
For a list of all languages (and their language codes) in which default stoplists are supplied, see Multilingual Features Matrix.
How to Load Your Own Stoplists
By default, only one drdefLANG.sql file is loaded during installation or upgrade based on the database language that you choose. You can call the CTX_DDL.LOAD_STOPLIST procedure to customize your stoplist or modify the default list of stopwords.
Unlike CTX_DDL.ADD_STOPWORD (which adds a single stopword per call), CTX_DDL.LOAD_STOPLIST takes a source file of stopwords for your specified language (from $ORACLE_HOME/ctx/data/stoplist/drstopLANG.txt) and loads to your stoplist.
Related Topics