Constructing CCL query
Common Command Language - CCL (ISO 8777) provides a symbolic language for expressing boolean query structures. The rules for creating a query are unambiguous and one can create complex queries as easily as the more trivial ones.
A query consists of a qualifier and a value separated by an equal sign. Many expressions can be combined with logical operators. There are three logical operators: "and", "or", and "not". If the value being searched consists of more than one word then it could be split and combined with the "and" operator, or surrounded by double quotes (") to preserve the spaces between the words.
Supported CCL qualifiers
The following, are commonly used CCL qualifiers. If there is a need to search additional indexes in a catalog, then other qualifiers can be added.
Nota:
For consistent results, the search index corresponding to any new qualifier must be supported in all catalogs being searched as part of a federated search.
| CCL Qualifier | Z39.50 Catalog Serch Index (common bib-1 use attribute) |
|---|---|
| au | Author (1 = 1003) |
| isbn | ISBN (1 = 7) |
| issn | ISSN (1 = 8) |
| su | Subject (1 = 21) |
| term | Term (1 = 1016) |
| titolo | Title (1 = 4) |
Examples of valid CCL queries
- Author query
- au="Albert Camus"
- ISBN query
- isbn=9781416548898
- Title query
- ti="Gone with the Wind"
- Term query
- term="Myth" or term="Sisyphus"
- Title and author query:
- ti="Gone with the Wind" and au="Mitchell" and au="Margaret"
- ti="Don Quixote" and au="Migue De Cervantes" or au="Edith Grossman"
URL encoding
The CCL query (query parameter value) must be percent-encoded when calling any DiscoveryItem services.