A zone section is a body of text delimited by start and end tags in a document. The positions of the start and end tags are recorded in the index so that any words in between the tags are considered to be within the section. Any instance of a zone section must have a start and an end tag.
For example, the text between the <TITLE> and </TITLE> tags can be defined as a zone section as follows:
<TITLE>Tale of Two Cities</TITLE> It was the best of times...
Zone sections can nest, overlap, and repeat within a document.
When querying zone sections, you use the WITHIN operator to search for a term across all sections. Oracle Text returns those documents that contain the term within the defined section.
Zone sections are well suited for defining sections in HTML and XML documents. To define a zone section, use CTX_DDL.ADD_ZONE_SECTION.
For example, assume you define the section booktitle as follows:
begin
ctx_ddl.create_section_group('htmgroup', 'HTML_SECTION_GROUP');
ctx_ddl.add_zone_section('htmgroup', 'booktitle', 'TITLE');
end;
After you index, you can search for all the documents that contain the term Cities within the section booktitle as follows:
'Cities WITHIN booktitle'
With multiple query terms such as (dog and cat) WITHIN booktitle, Oracle Text returns those documents that contain cat and dog within the same instance of a booktitle section.
Repeated Zone 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 Brown WITHIN Heading returns this document. However, a query of (Brown and Gray) WITHIN Heading does not.
Overlapping Zone Sections
Zone sections can overlap each other. For example, if <B> and <I> denote two different zone sections, they can overlap in a document as follows:
plain <B> bold <I> bold and italic </B> only italic </I> plain
Nested Zone 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. 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.