Assumptions Made in this Chapter's Examples

XML text is aVARCHAR2 or CLOB type in an Oracle8i database table with character semantics.

interMedia Text can also deal with documents on a file system or on URLs. We do not consider these document types here.

To simplify the examples included in this chapter we consider a subset of the interMedia Text options.

We have made the following assumptions here:

• All XML data here is represented using US-ASCII, a 7 bit character set.

• Issues about whether a character such as "*" is treated as white space or as part of a word are not included.

• Storage characteristics of the Oracle schema object that implement the TEXT index are not considered.

• We focus here on the SECTION GROUP parameter in the CREATE INDEX or ALTER INDEX statement¹. Here is an example of using SECTION GROUP in CREATE INDEX:

  CREATE INDEX my_index 
    ON my_table ( my_column ) 
    INDEXTYPE IS ctxsys.context 
    PARAMETERS ( 'SECTION GROUP my_section_group' ) ; 
  

• Specifically, we focus on using AUTO_SECTION_GROUP and XML_SECTION_GROUP.

• Tagged or marked up data. We focus here on how to handle XML data. interMedia Text handles many other kinds of data.

---

¹ Other parameter types are available for CREATE INDEX and ALTER INDEX. These are DATASTORE, FILTER, LEXER, STOPLIST, and WORDLIST.