Proximity Search

• A basic linguistic assumption is that the proximity of words implies a relationship between them.

• Proximity search helps match phrases while avoiding scattered or spread-out terms in the text.

• By limiting the search to only include matches where the terms are within the specified maximum proximity,
  the search results can be more relevant than those with scattered terms.

• When searching with some specified distance between search terms term1 and term2:

  • Retrieved documents will contain text in which term1 and term2 are separated by
    the maximum number of terms specified or less.

  • The search terms can be separated by fewer terms, but not more than the specified distance.

  • Only the terms generated by the search analyzer are considered towards the count of the maximum distance.
    Words or tokens that are Not part of the generated terms are Not included in the proximity calculation.

• Note:

  • Search criteria should contain at least 2 search terms.

  • Search terms must be simple string terms without wildcards.

Proximity search (0 distance)

/** @var array<Employee> $employees */
$employees = $session->advanced()
    ->documentQuery(Employee::class)
    // Make a full-text search with search terms
    ->search("Notes", "fluent french")
    // Call 'Proximity' with 0 distance
    ->proximity(0)
    ->toList();

from "Employees"
where proximity(search(Notes, "fluent french"), 0)

Running the above query on the Northwind sample data returns the following Employee documents: employees/2-A
employees/5-A
employees/9-A

Each resulting document has the text 'fluent in French' in its 'Notes' field.

The word "in" is not taken into account as it is Not part of the terms list generated by the analyzer. (Search is case-insensitive in this case.)

Proximity search (distance > 0)

/** @var array<Employee> $employees */
$employees = $session->advanced()
    ->documentQuery(Employee::class)
    // Make a full-text search with search terms
    ->search("Notes", "fluent french")
    // Call 'Proximity' with distance 5
    ->proximity(4)
    ->toList();

from "Employees"
where proximity(search(Notes, "fluent french"), 5)

Running the above query on the Northwind sample data returns the following Employee documents: employees/2-A
employees/5-A
employees/6-A
employees/9-A

This time document 'employees/6-A' was added to the previous results since it contains the phrase: "fluent in Japanese and can read and write French" where the search terms are separated by a count of 4 terms.

"in" & "and" are not taken into account as they are not part of the terms list generated by the analyzer.(Search is case-insensitive in this case).

public function proximity(int $proximity): DocumentQueryInterface;