The Crossref Curriculum

Controlling query execution

Some query elements have optional properties that control how a query is executed by the XML API. The Crossref query engine operates by evaluating several logic rules in series. Each rule focuses on certain fields in the query, with the first rule processing the entire query. If any rule returns a single metadata record as its output, this DOI is taken as the result for the query, and rule processing terminates.

Controls include:

  • Match: use to specify level of fuzzy or exact matching. This attribute may be applied to several elements (ISSN, author, issue, article_title)
  • Enable-multiple-hits: allows or prevents matches returning more than one DOI
  • Secondary-query: instructs the system to perform a specific query if the default query mode does not produce a result. Current options include author/title, multiple hits, and author/title multiple hits.

Table of query controls

Element Property Value Purpose
query key string to track a query to its results
query enable-multiple-hits false (default) have the system reduce the query to one DOI and return nothing if it can not do so
query enable-multiple-hits true have the system return one DOI for each query rule it executes
query enable-multiple-hits multi_hit_per_rule have the system return many DOIs for each query rule it executes - will produce up to 50 candidate DOIs which partially match the query
query enable-multiple-hits exact rule processing is disabled, all DOIs matching a simple comparison to query values are returned
query forward-match false (default) no query is stored
query forward-match true store this query and re-run it automatically and notify via email any matches that are found
query list-components false (default) components not included in results
query list-components true list the DOIs of any components that have deposited which are linked to this DOI
query expanded-results false (default) will not include article title in results
query expanded-results true include article title in the results (only applicable when results format=XML_XSD)
query secondary-query author-title perform author-title search if metadata search fails
query secondary-query multiple-hits returns multiple hits (if present)
query secondary-query author-title-multiple-hits performs author/title and multiple hits search if initial search fails
issn match optional value may be missing from deposited metadata
issn match exact match exactly as it appears in the query
journal_title match optional not required
journal_title match fuzzy (default) use fuzzy string matching
journal_title match exact match exactly as it appears in the query
author match optional instructs the query engine that this field may be ignored
author match fuzzy (default) use fuzzy string matching
author match null match if author is missing in the metadata
author match exact match exactly as it appears in the query
issue match fuzzy (default) / exact – see above –
first_page match fuzzy (default) / exact – see above –
year match optional (default) / exact – see above –
article_title match fuzzy (default) / exact – see above –

Last Updated: 2020 April 8 by Laura J. Wilkinson