Highlighting Query Terms

In Oracle Text query applications, you can present selected documents with query terms highlighted for text queries or with themes highlighted for ABOUT queries.

You can generate three types of output associated with highlighting: a marked-up version of the document, a plain text version of the document (filtered output), and highlight offset information for the document.

The three types of output are generated by three different procedures in the CTX_DOC (document services) PL/SQL package. In addition, you can obtain plain text and HTML versions for each type of output.

Text highlighting

For text highlighting, you supply the query, and Oracle highlights words in document that satisfy the query. You can obtain plain-text or HTML highlighting.

Theme Highlighting

For ABOUT queries, the CTX_DOC procedures highlight and mark up words or phrases that best represent the ABOUT query.

CTX_DOC Highlighting Procedures

There are three highlighting procedures in CTX_DOC:

• HIGHLIGHT

• MARKUP

• FILTER

Highlight Procedure

Highlight offset information is useful for when you write your own custom routines for displaying documents.

To obtain highlight offset information, use the CTX_DOC.HIGHLIGHT procedure. This procedure takes a query and a document, and returns highlight offset information for either plaintext or HTML formats.

With offset information, you can display a highlighted version of document as desired. For example, you can display the document with different font types or colors rather than using the standard plain text markup obtained from CTX_DOC.MARKUP.

See Also: Oracle Text Reference for more information about using CTX_DOC.HIGHLIGHT.

Markup Procedure

The CTX_DOC.MARKUP procedure takes a document reference and a query, and returns a marked-up version of the document. The output can be either marked-up plaintext or marked-up HTML.

You can customize the markup sequence for HTML navigation.

See Also: Oracle Text Reference for more information about CTX_DOC.MARKUP.

Filter Procedure

When documents are stored in their native formats such as Microsoft Word, you can use the filter procedure CTX_DOC.FILTER to obtain either a plain text or HTML version of the document.

See Also: Oracle Text Reference for more information about CTX_DOC.FILTER.