Creating a Text Policy

An Oracle Text policy specifies how text content should be interpreted. You can provide a text policy to govern a model, an attribute, or both the model and individual attributes. If a model-specific policy is present and one or more attributes have their own policies, Oracle Data Mining uses the attribute policies for the specified attributes and the model-specific policy for the other attributes.

The CTX_DDL.CREATE_POLICY procedure creates a text policy.

CTX_DDL.CREATE_POLICY(
          policy_name    IN VARCHAR2,
                                        filter         IN VARCHAR2 DEFAULT NULL,
                                        section_group  IN VARCHAR2 DEFAULT NULL,
                                        lexer          IN VARCHAR2 DEFAULT NULL,
                                        stoplist       IN VARCHAR2 DEFAULT NULL,
                                        wordlist       IN VARCHAR2 DEFAULT NULL);

The parameters of CTX_DDL.CREATE_POLICY are described in Table 7-5.

Table 7-5 CTX_DDL.CREATE_POLICY Procedure Parameters

Parameter Name	Description
`policy_name`	Name of the new policy object. Oracle Text policies and text indexes share the same namespace.
`filter`	Specifies how the documents should be converted to plain text for indexing. Examples are: `CHARSET_FILTER` for character sets and `NULL_FILTER` for plain text, HTML and XML. For `filter` values, see "Filter Types" in Oracle Text Reference.
`section_group`	Identifies sections within the documents. For example, `HTML_SECTION_GROUP` defines sections in HTML documents. For `section_group` values, see "Section Group Types" in Oracle Text Reference. Note: You can specify any section group that is supported by `CONTEXT` indexes.
`lexer`	Identifies the language that is being indexed. For example, `BASIC_LEXER` is the lexer for extracting terms from text in languages that use white space delimited words (such as English and most western European languages). For `lexer` values, see "Lexer Types" in Oracle Text Reference.
`stoplist`	Specifies words and themes to exclude from term extraction. For example, the word "the" would typically be in the stoplist for English language documents. The system-supplied stoplist is used by default. See "Stoplists" in Oracle Text Reference.
`wordlist`	Specifies how stems and fuzzy queries should be expanded. A stem defines a root form of a word so that different grammatical forms have a single representation. A fuzzy query includes common misspellings in the representation of a word. See `BASIC_WORDLIST` in Oracle Text Reference.