|Oracle Text Reference
Part Number A90121-01
CONTAINS Query Operators, 3 of 28
In all languages, an ABOUT query increases the number of relevant documents returned from the same query without this operator. Oracle scores results for an ABOUT query with the most relevant document receiving the highest score.
In English and French, use the ABOUT operator to query on concepts. The system looks up concept information in the theme component of the index.
Oracle retrieves documents that contain concepts that are related to your query word or phrase. For example, if you issue an ABOUT query on California, the system might return documents that contain the terms Los Angeles and San Francisco, which are cities in California.The document need not contain the term California to be returned in this ABOUT query.
The word or phrase specified in your ABOUT query need not exactly match the themes stored in the index. Oracle normalizes the word or phrase before performing lookup in the index.
You can use the ABOUT operator with the CONTAINS and CATSEARCH SQL operators.
The ABOUT operator uses the supplied knowledge base in English and French to interpret the phrase you enter. Your ABOUT query therefore is limited to knowing and interpreting the concepts in the knowledge base.
You can improve the results of your ABOUT queries by adding your application-specific terminology to the knowledge base.
In all languages, increases the number of relevant documents returned for the same query without the ABOUT operator.The phrase parameter can be a single word or a phrase, or a string of words in free text format.
The phrase you specify cannot be more than 4000 characters.
ABOUT queries give the best results when your query is formulated with proper case. This is because the normalization of your query is based on the knowledge catalog which is case-sensitive.
However, you need not type your query in exact case to obtain results from an ABOUT query. The system does its best to interpret your query. For example, if you enter a query of CISCO and the system does not find this in the knowledge catalog, the system might use Cisco as a related concept for look-up.
The phrase you specify in an ABOUT query cannot be more than 4000 characters.
To search for documents that are about soccer, use the following syntax:
You can further refine the query to include documents about soccer rules in international competition by entering the phrase as the query term:
In this English example, Oracle returns all documents that have themes of soccer, rules, or international competition.
In terms of scoring, documents which have all three themes will generally score higher than documents that have only one or two of the themes.
You can also query on unstructured phrases, such as the following:
You can use other operators, such as AND or NOT, to combine ABOUT queries with word queries.
For example, you can issue the following combined ABOUT and word query:
You can combine an ABOUT query with another ABOUT query as follows: