Phrase Prefix - Paradedb

Phrase prefix identifies documents containing a phrase followed by a term prefix.

<CodeGroup> ```sql SQL SELECT description, rating, category FROM mock_items WHERE description @@@ pdb.phrase_prefix(ARRAY['running', 'sh']); ```

python

from paradedb import ParadeDB, PhrasePrefix

MockItem.objects.filter(
    description=ParadeDB(PhrasePrefix('running', 'sh'))
).values('description', 'rating', 'category')

python

from sqlalchemy import select
from sqlalchemy.orm import Session
from paradedb.sqlalchemy import search

stmt = (
    select(MockItem.description, MockItem.rating, MockItem.category)
    .where(search.phrase_prefix(MockItem.description, ["running", "sh"]))
)

with Session(engine) as session:
    session.execute(stmt).all()

ruby

MockItem.search(:description)
        .phrase_prefix("running", "sh")
        .select(:description, :rating, :category)

</CodeGroup> <div className="mt-8" /> <ParamField body="phrases" required> An `ARRAY` of tokens that the search is looking to match, followed by a term prefix rather than a complete term. </ParamField> <ParamField body="max_expansions" default={50}> Limits the number of term variations that the prefix can expand to during the search. This helps in controlling the breadth of the search by setting a cap on how many different terms the prefix can match. </ParamField>

Performance Considerations

Expanding a prefix might lead to thousands of matching terms, which impacts search times.

With max_expansions, the prefix term is expanded to at most max_expansions terms in lexicographic order. For instance, if sh matches shall, share, shoe, and shore but max_expansions is set to 3, sh will only be expanded to shall, share, and shoe.