Oracle Text

Oracle Text works with regular data columns, blob and doc, pdf files stored.
There are different index types for oracle text:

CTXCAT Indexes

A CTXCAT index is best for smaller text fragments that must be indexed along with other standard relational data (VARCHAR2).

example:
WHERE CATSEARCH(text_column, 'ipod')> 0;


CONTEXT Indexes

The CONTEXT index type is used to index large amounts of text such as Word, PDF, XML, HTML or plain text documents.

ex: WHERE CONTAINS(test_column, 'ipod', 1) > 0

CTXRULE Indexes
A CTXRULE index can be used to build document classification applications.