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ISABOUT Term

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While this feature is still supported in the current product version, it may be removed in the future. If you write new applications, avoid using this deprecated feature. If you modify existing applications, you are strongly encouraged to remove any dependency on this feature.

The ISABOUT term matches columns against a group of one or more search terms. It has the following syntax:

ISABOUT(<components>) [RANKMETHOD <method>]

The optional RANKMETHOD term specifies the calculation method used to rank the documents that match one or more of the components. If no RANKMETHOD is specified, the default Jaccard Coefficient ranking method is used. For more information about using RANKMETHOD, see RANKMETHOD Term.

The ISABOUT term can have one or more components. The columns specified in the CONTAINS predicate are tested against each component. The document is included with the results if at least one of the components matches. Commas separate multiple components.

Following is the component part syntax:

<match_term> [<weight_term>]

You can use the optional WEIGHT term to change the relative importance of each term within the ISABOUT term. If no weight term is applied, the default 1.0 weight is implied.

The following table describes possible match term types.

Type Description Examples
Word A single word without spaces or other punctuation. 
...WHERE CONTAINS
 ('
 ISABOUT ("computer","software")
 ')
Phrase Multiple words or included spaces. 
...WHERE CONTAINS
 ('
 ISABOUT ("computer software","hardware")
 ')
Wildcard Words or phrases with the asterisk (*) added to the end. For more information, see Using Wildcards in the CONTAINS Predicate. 
...WHERE CONTAINS
 ('
 ISABOUT ("compu*","soft*")
 ')
Matches "computer", "computers", "computation", 
and "compulsory"

ISABOUT Column Weighting

The ISABOUT term ranks matching documents based on how closely each document matches the set of match terms in the query. You can use column weighting to place more importance on matching some match terms compared to others. Each match term in the ISABOUT term can have a weight value applied. The WEIGHT term has two alternative syntaxes.

The long syntax follows:

<match_term> WEIGHT(<weight_value>)

The weight is applied to a single match term, and is indicated by the keyword "WEIGHT".

The weight value must be between 0 and 1.0, with no more than three decimal places. Specifying any weight values outside this range results in an error message. The weights are multiplied against the unweighted ranking value.

If no weight is specified for a match term, the default value, 1.0, is implied.

Example

The following example applies weights to the two ISABOUT match terms, using the long and shortened weight indicators.

...WHERE CONTAINS(
"System.FileName",
'ISABOUT("computer" WEIGHT (0.75),"software":0.25)')