Searching separate fields

When we built our index, we used prefixes to separate the terms generated from the title and description fields. This allows us to perform searches which are restricted to the text in just one of those fields, by searching only terms with the desired prefix.

When using the Query Parser, it is possible to restrict your search to certain prefixed terms (e.g. title, or description). These can be searched for either by using a search prefix (which can correlate to an indexing prefix) or as a general text document.

To set up a search prefix, the QueryParser needs to be told which prefixes in the search query relate to those in the index. We did that in the previous search code:

    queryparser.add_prefix("title", "S")
    queryparser.add_prefix("description", "XD")

This allows us to perform a search based on either field, for example:

$ python3 code/python3/search1.py db title:sunwatch
1: #001 Ansonia Sunwatch (pocket compas dial)
'title:sunwatch'[0:10] = 1

We can also combine prefixes with the logical operators to perform more complex queries (note that we need to escape quotes or else the shell will eat them):

$ python3 code/python3/search1.py db description:\"leather case\" AND title:sundial
1: #055 Silver altitude sundial in leather case
'description:"leather case" AND title:sundial'[0:10] = 55