Enabling Wildcard Support at the Project Level
About this task
As discussed in Default Query Syntax, Watson™ Explorer Engine supports both wildcards and regular expressions in queries. Wildcard support can be enabled either at the project level or the search collection level.
In most cases, wildcards should be enabled at the search collection level. You will only need to enable wildcards at the project level if you want to add wildcard support for federated sources. (Federated sources are not associated with a search collection because they retrieve results from another search engine.)
To enable wildcard support at the project level, do the following:
- Select the project's Advanced -> Metasearch tab.
- Click the edit button, and scroll down to the Query Modification section.
- Set Enable wildcard expansion to true. Once you set Enable wildcard expansion to true, Watson Explorer Engine will automatically use the default wildcard dictionary file unless a custom dictionary is identified in the Dictionary file field.
The options related to wildcard support in Watson Explorer Engine projects are the following:
- Minimum length of wildcard term - The minimum number of sequential characters required in a query term containing a wildcard character in order for the expansion to take place. This improves performance and helps to minimize the number of query terms generated.
- Dictionary file - The full path to the wildcard dictionary file to use for expansions.
- Wildcard segmenter - Specifies the segmenter algorithm to use for the wildcard
expansion. A segmenter is used to take sequential statements in non-segmented languages
(for example, Japanese or Chinese) and divide the statement into the individual components
or words. Note: The use of wildcard segmentation is not recommended. A query that includes wildcards expands each wildcarded statement into a list of possible statements from the wildcard dictionary. These statements are then split into components or words by the segmenter. Some of the components that are created may have only been created due to a specific wildcard, and be completely unrelated to the original query; this can have a significant impact on the usefulness of any search results.
- Wildcard should delanguage - Set to true, this option attempts to normalize the diacritics and different writing systems before expanding wildcard operators.