Creating Sections in XML Documents that are Document Type Sensitive

Consider an XML document set that contains the <book> tag declared for different document types. You need to create a distinct book section for each document type. Assume that mydocname is declared as an XML document type (root element) as follows:

<!DOCTYPE mydocname ... [...

Within mydocname, the element <book> is declared. For this tag, you can create a section named mybooksec that is sensitive to the tag's document type as follows:

begin
ctx_ddl.create_section_group('myxmlgroup', 'XML_SECTION_GROUP');
ctx_ddl.add_zone_section('myxmlgroup', 'mybooksec', 'mydocname(book)');
end;

Note: Oracle8i knows what the end tags look like from the group_type parameter you specify when you create the section group. The start tag you specify must be unique within a section group. Section names need not be unique across tags. You can assign the same section name to more than one tag, making details transparent to searches.

Repeated Sections

Zone sections can repeat. Each occurrence is treated as a separate section. For example, if <H1> denotes a heading section, they can repeat in the same documents as follows:

<H1> The Brown Fox </H1> 
<H1> The Gray Wolf </H1> 

Assuming that these zone sections are named Heading.

The query:

WHERE CONTAINS (..., 'Brown WITHIN Heading', ...)... 

returns this document.

But the query:

WHERE CONTAINS (...,' (Brown and Gray) WITHIN Heading',...)...

does not.

Overlapping Sections

Zone sections can overlap each other. For example, if <B> and <I> denote two different zone sections, they can overlap in document as follows:

plain <B> bold <I> bold and italic </B> only italic </I>  plain

Nested Sections

Zone sections can nest, including themselves as follows:

<TD> 
  <TABLE>
  <TD>nested cell</TD>
  </TABLE>
</TD>

Using the WITHIN operator, you can write queries to search for text in sections within sections.

Nested Section Query Example

For example, assume the BOOK1, BOOK2, and AUTHOR zone sections occur as follows in documents doc1 and doc2:

doc1:

<book1><author>Scott Tiger</author> This is a cool book to read.</book1>

doc2:

<book2> <author>Scott Tiger</author> This is a great book to read.</book2>

Consider the nested query:

'Scott WITHIN author WITHIN book1'

This query returns only doc1.