Which has the higher priority in your organization: Deploying a new database or securing the ones you already have?
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According to the Oracle Text Reference online doc the CTX_ANL PL/SQL package is used with AUTO_LEXER and provides procedures for adding and dropping a custom dictionary from the lexer.
A custom dictionary might be one that you develop for a special field of study or for your industry. In most cases, the dictionaries supplied with Oracle Text are more than sufficient to handle your requirements.
Owned by CTXSYS with EXECUTE granted to the CTXAPP role.