public function SearchQuery::addScore

Adds a custom score expression to the search query.

Score expressions are used to order search results. If no calls to addScore() have taken place, a default keyword relevance score will be used. However, if at least one call to addScore() has taken place, the keyword relevance score is not automatically added.

Note that you must use this method to add ordering to your searches, and not call orderBy() directly, when using the SearchQuery extender. This is because of the two-pass system the SearchQuery class uses to normalize scores.

Parameters

string $score: The score expression, which should evaluate to a number between 0 and 1. The string 'i.relevance' in a score expression will be replaced by a measure of keyword relevance between 0 and 1.

array $arguments: Query arguments needed to provide values to the score expression.

float $multiply: If set, the score is multiplied with this value. However, all scores with multipliers are then divided by the total of all multipliers, so that overall, the normalization is maintained.

Return value

$this

File

core/modules/search/src/SearchQuery.php, line 502

Class

SearchQuery

Search query extender and helper functions.

Namespace

Code

public function addScore($score, $arguments = [], $multiply = FALSE) {
  if ($multiply) {
    $i = count($this->multiply);

    // Modify the score expression so it is multiplied by the multiplier,
    // with a divisor to renormalize. Note that the ROUND here is necessary
    // for PostgreSQL and SQLite in order to ensure that the :multiply_* and
    // :total_* arguments are treated as a numeric type, because the
    // PostgreSQL PDO driver sometimes puts values in as strings instead of
    // numbers in complex expressions like this.
    $score = "(ROUND(:multiply_{$i}, 4)) * COALESCE(({$score}), 0) / (ROUND(:total_{$i}, 4))";

    // Add an argument for the multiplier. The :total_$i argument is taken
    // care of in the execute() method, which is when the total divisor is
    // calculated.
    $arguments[':multiply_' . $i] = $multiply;
    $this->multiply[] = $multiply;
  }

  // Search scoring needs a way to include a keyword relevance in the score.
  // For historical reasons, this is done by putting 'i.relevance' into the
  // search expression. So, use string replacement to change this to a
  // calculated query expression, counting the number of occurrences so
  // in the execute() method we can add arguments.
  while (str_contains($score, 'i.relevance')) {
    $pieces = explode('i.relevance', $score, 2);
    $score = implode('((ROUND(:normalization_' . $this->relevance_count . ', 4)) * i.score * t.count)', $pieces);
    $this->relevance_count++;
  }
  $this->scores[] = $score;
  $this->scoresArguments += $arguments;
  return $this;
}