# Combine

The method to use to combine similar results. You can use this option when your index contains document sections or duplicate documents, to ensure that each document returns only a single result.

By default, when IDOL Server combines multiple results, it returns the result with the highest relevance. You can use the Sort action parameter to use an alternative sorting method, in which case it returns the result that scores highest for your Sort method.

Set `Combine` to one of the following values:

`Simple` | Combine sections of the same document. Micro Focus recommends this `Combine` option. When you index very long texts, IDOL Server splits them up into sections and indexes each section as an individual document. Each section has its own document ID, but all sections of the document have the same document reference. This process improves the stability of the indexing process, and ensures that IDOL Server returns only the most relevant sections of a text. However, when multiple sections match a query, IDOL Server might return multiple results that have the same document reference (for example, different pages of the same book), and if you set Print to `AllSections`, you receive the same text for each result. Set `Combine` to `Simple` to return only one section of each result document. In this case, IDOL Server returns the section that has the highest score in the Sort for your query (by default, the highest relevance). If multiple sections have the same score, IDOL Server returns the one with the lowest section number.
`ReferenceField` | Combine results that have the same value in the specified ReferenceType field. Set `Combine` to the name of the ReferenceType field to combine by the value of this field. If multiple query results have the same value in this field, IDOL Server returns only the result that has the highest score in the Sort for your query (by default, the highest relevance). If several results have the same score, it returns the result with the highest `DocID`. NOTE: Avoid using the `DREREFERENCE` field to combine results, because it can slow down the `Combine` process.
`FieldCheck` | Combine results that have the same hash value of their FieldCheckType field. The FieldCheckType field holds a value that you use frequently to restrict results (for example, a field that stores category names). When IDOL Server indexes a FieldCheckType field, it stores it in a fast-look-up table in memory, so that it can return it quickly. Set `Combine` to `FieldCheck` to return only one result for each value in the FieldCheckType field. NOTE: You cannot use FieldCheckType fields if you set URLAnalysis to `True` in your IDOL Server configuration file, because IDOL Server automatically uses the domain of the URL it finds in the document ReferenceType fields as the `FieldCheck` value.
`MetadataField` | Combine results that have the same value in a metadata field. You can use the following metadata fields: `<autn_database>` `<autn_language>` `<autn_langtype>` For example:
    Combine=<autn_database>
If you set `Combine` to a metadata field, you can use CombineNumber to retrieve the top `N` hits for each value. For example, you can return the top 10 results in a particular database.

By default, IDOL Server combines any result documents that do not have a FieldCheckType field or the specified ReferenceType field into a single result. To return these results separately, set the CombineIgnoreMissingValue configuration parameter to `True`.

You can combine the `Simple` and `FieldCheck` options, in which case you must specify `Simple` first. For example:

    Combine=Simple+FieldCheck

You can also combine the `Simple` and `ReferenceField` options. For example:

    Combine=Simple+MyReferenceField

Actions: | Query Suggest SuggestOnText GetQueryTagValues
Type: | String
Default: |
Recommended Value: | Simple
Example: | `action=Query&Text=The Moonstone&Combine=Simple` In this example, if several results derive from the same source text, IDOL Server displays only the document section that has the highest relevance to the query text. `action=Query&Text=The Moonstone&Combine=TitleRef` In this example, if several results contain the same value in the `TitleRef` field, IDOL Server displays only the result that has the highest relevance to the query text. The `TitleRef` field must be configured as a ReferenceType field.
See Also: | CombineNumber CombineIgnoreMissingValue configuration parameter FieldCheckType configuration parameter ReferenceType configuration parameter URLAnalysis configuration parameter

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