Configuring Query Expansion for Application Builder

This section describes how to configure automatic and suggested search query expansions for your application.

About this task

Query expansion is the process of automatically or manually increasing the terms in a search query by selecting them from a taxonomy of related terms. Query expansion options can be found in the Settings > Search section of the Application Builder settings page (the cog icon on the navigation bar).

Before query expansion can be used in an application, a Watson Explorer Engine ontolection must exist. For information about onotolections, see Creating an Ontolection.

Note: You can use the natural language querying Ontolection Trainer component of Watson Explorer Engine to train an ontolection, which you can then use with query expansion.

After you create one or more ontolections, you can use them to provide query expansion with the following settings:

Enable query expansion - When set to on, the application will use any query expansion stores that are defined to automatically perform semantic expansion of search queries. The default is on.
Hide list of expanded terms for query - When set to on, the application will automatically expand any automatically expanded types, but will not display the query expansion information to the user. The default is off.
Choose query expansion collections - A list of collections on your backends. Select one or more ontolections that you want to use in your application.
Note: Make sure to select only valid Watson Explorer Engine ontolections. Selecting other collections can cause unexpected results.
Specify types to automatically expand - The list of types that will be automatically expanded when a user performs a query. The types that will be automatically expanded must be entered into the field as a newline separated list of types. For example, you might want the spelling type to be expanded automatically, but the synonym type to be expanded at the user's discretion. In that case you would enter spelling into the field and omit synonym. If no value is specified in this field (the default), all available types are automatically expanded. The types that are available depend on the data in your ontolection. You can see the types that a crawled ontolection has available by looking at the content names that are present (other than term, which is the type for the main word). For a list of example types that might be created when crawling an ontolection, see Exploring the Sample Thesaurus.
Specify maximum number of expansions per type - If you want to change the number of expansions that are included in the user's search, specify a number that is greater or less than the default (5).

When a user enters a query into the search box, the system looks for expansions in the ontolections that have been defined as query expansion stores, trying to match the set of single terms, any quoted phrases, and the entire query string. For example, if the following set of terms and expansions are available in a query-expansion-store:

color => colour (spelling)
car => automobile (synonym)
car color => paint job (synonym)

When all expansions are active, the query new car color would become new AND (car OR automobile) AND (color OR colour).

The query new "car color" would become new AND (car color OR paint job). The expanded query continues to follow this sort of logic and becomes more complex when multiple expansion terms (words and phrases) overlap.

When enabled, query expansion options are available to the user at the top of the search results widget, and are only visible when the query has expansions available.