Ferret

QueryParser

You’ve now been introduced to all the different types of queries available in Ferret, and you’ve learned how to build different queries by hand. Some of it probably seems like a lot of work and it’s certainly not something you’d ask a user to do. Luckily, we can leave most of the work to the Ferret QueryParser. You’ve already seen many examples of the Ferret Query Language (FQL) in the previous section (Building Queries”), and you’ll have noticed that most of the queries you can build in code can be described much more easily in FQL. In this section, we’ll talk about setting up the QueryParser, and then we’ll go into more detail about FQL.

Setting Up the QueryParser

The QueryParser has a number of parameters, as shown in Table 4-1.

Table 4-1. QueryParser parameters

Parameter	Default	Short description
:default_field	:*	The default field to be searched; it can also be an array.
:analyzer	StandardAnalyzer	Analyzer used by the query parser to parse query terms.
:wild_card_downcase	true	Specifies whether wildcard queries should be downcased or not, since they are not analyzed by the parser.
:fields	[]	Lets the query parser know what fields are available for searching, particularly when the :* is specified as the search field.
:validate_fields	false	Set to true if you want an exception to be raised if there is an attempt to search a nonexistent field.
:or_default	true	Use OR as the default Boolean operator.
:default_slop	0	Default slop to use in PhraseQueries.
:handle_parser_errors ...