Query

Introduction

Query is a helper function that is used to create Solr query string. It’s basically just a dict, but we make it aware of how it should handle certain keys.

A query has 3 major parts. The Facet parameters, Highlighting parameter and query parameters themselves. The first thing Query does is add the default Facet and Highlighting params. Then it parses the arguments in a clean function and creates a dictionary. Simple example:

>>> from solango.solr.query import Query
>>> q = Query(q='django', model='coltrane_entry`)
{'facet.field': u'model',
 'fl': [],
 'fq': [],
 'hl.fl': u'text',
 'op': u'OR',
 'q': ['django', 'model:coltrane_entry']],
 'rows': u'10',
 'sort': [],
 'start': u'0'}
>>> q.url
'rows=10&facet.field=model&facet.field=author&q=django+AND+model%3Acoltrane_entry
&start=0&hl.fl=text&hl.fragsize=200&q.op=OR&facet=true&hl=true'

If you notice q is a list. It assumes that anything that isn’t a default query param is a search params. So in the url we join all the search parameters by ANDing them together.

Facet

Facet params start with facet and the full list of options can be found on the Solr Simple Facet Parameters. page

As an example we want to set a new facet.offset of one we pass that into the query or set the attribute.:

# Pass it into the Query
>>> q = Query({'facet.offset':1} ,q='django')
>>> q
{'facet.field': u'author',
 'facet.field': u'model',
 'facet.offset': u'1',
 ...}

# Set the attribute
>>> q = Query(q='django')
>>> q.facet.offset = 1
>>> q
{'facet.field': u'author',
 'facet.field': u'model',
 'facet.offset': u'1',
 ...}

This is done by using a util data structure we have affectionately named CleverDict.

Highlighting

Highlighting params work the same way and the full list of options can be found on the Solr Highlighting Parameters. page

Not every option may be supported.

Operator

By default Solr uses OR to join all the terms within any query, so q=”John Smith” is searched as q=”John OR Smith”. There are a couple of ways to fix this, you can set it in the schema.xml so every time a search is made it defaults to AND. You can set it by setting SOLR_DEFAULT_OPERATOR in your settings.py file like so:

SOLR_DEFAULT_OPERATOR = 'AND'

The other way is through the query syntax:

>>> from solango.solr.query import Query
>>> q = Query(q='django development', op='AND')
>>> q.url
'rows=10&facet.field=model&facet.field=author&q=django+development&start=0&hl.fl=text&hl.fragsize=200&q.op=AND&facet=true&hl=true'

# Select using AND.
>>> import solango
>>> r = solango.connection.select(q)
>>> r.count
9

# Select using OR. We get more results.
>>> q = Query(q='django development', op='OR')
>>> r = solango.connection.select(q)
>>> r.count
14