tripal/tripal_views/views/handlers/views_handler_join_chado_aggregator.inc

<?php

/**
 * @file
 * Handler to allow joins between records via a linking table
 *
 * Example Usage:
 *   To join the analysisprop table to the analysis table,
 *   Use the following code in the analysisprop hook_views_data:
 *   @code
        $data['analysisprop']['table']['join']['analysis'] = array(
          'left_field' => 'analysis_id',
          'field' => 'analysis_id',
          'handler' => 'views_handler_join_chado_aggregator'
        );
 *   @endcode
 */
class views_handler_join_chado_aggregator extends views_join {

  // PHP 4 doesn't call constructors of the base class automatically from a
  // constructor of a derived class. It is your responsibility to propagate
  // the call to constructors upstream where appropriate.
  function construct($table = NULL, $left_table = NULL, $left_field = NULL, $field = NULL, $extra = array(), $type = 'LEFT', $added = NULL) {
    parent::construct($table, $left_table, $left_field, $field, $extra, $type);

    // Determine the postgresql version
    $postgresql_version = pg_version();
    $this->postgresql_version = $postgresql_version['client'];

    // If version is 9.0+ then indicate
    // Needed to apply sorting for aggregated fields
    if (intval($postgresql_version['client']) >= 9) {
      $this->postgresql_9up = TRUE;
    }

  }

  /**
   * Creates SQL including aggregation query used in join
   */
  function join($table, &$query) {
    $output = array();

    // Create the table SQL (used in join) -------
    // query creating one-to-one table using array_agg
    $table_desc = module_invoke_all('chado_' . $this->definition['table'] . '_schema');
    $select_fields[ $this->definition['table'] ] = $table_desc['fields'];

    // Add joins to tables with a foreign key in this table
    // (ie: add join to cvterm if this table has a type_id
    $joins = array();
    foreach ($table_desc['foreign keys'] as $defn) {
      if ($defn['table'] != $this->left_table) {
        foreach ( $defn['columns'] as $left => $right) {
          $left = $this->definition['table'] .'.'. $left;
          $right = $defn['table'] .'.'. $right;
          $joins[] = "LEFT JOIN $defn[table] $defn[table] ON $left=$right";
        }

        // Fields to be selected from joined table
        $join_table = module_invoke_all('chado_' . $defn['table'] . '_schema');
        $select_fields[ $defn['table'] ] = $join_table['fields'];
      }
    }

    // Determine Order BY's for aggregates
    $order_by = array();
    foreach ($this->sort as $s) {
      $order_by[] = $s['table'] . '.' . $s['field'] . ' ' . $s['order'];
    }


    // Fields to be selected
    foreach ($select_fields as $table => $table_fields) {
      foreach ($table_fields as $fname => $f) {
        $alias = '';
        if ($table != $this->definition['table']) {
          $alias = $table .'_';
        }

        if ($fname != $this->definition['field']) {
          // Add sort to aggregate field if postgreSQL 9.0+
          if ($this->postgresql_9up && !empty($order_by)) {
            $fields[] = 'array_agg(' . $table . '.' . $fname . ' ORDER BY ' . implode(',', $order_by) . ') as ' . $alias . $fname;
          }
          else {
            $fields[] = 'array_agg(' . $table . '.' . $fname . ') as ' . $alias . $fname;
          }
          $composite_field_parts[] = "'" . $alias . $fname . "::' ||" . $table . '.' . $fname;
        }
        else {
          $fields[] = $fname;
          $composite_field_parts[] = "'" . $alias . $fname . "::' ||" . $table . '.' . $fname;
        }
      }
    }

    // composite field
    // (combines all other fields before aggregating)
    // Add sort to aggregate field if postgreSQL 9.0+
    if ($this->postgresql_9up && !empty($order_by)) {
      $composite_field = "array_agg('{'||" . implode(" || ',' || ", $composite_field_parts) . "||'}' ORDER BY " . implode(',', $order_by) . ") as all";
    }
    else {
      $composite_field = "array_agg('{'||" . implode(" || ',' || ", $composite_field_parts) . "||'}') as all";
    }
    $fields[] = $composite_field;

    // SQL to use in the join
    $sql = 'SELECT ' . implode(', ', $fields)
      .' FROM ' . $this->definition['table']
      .' ' . implode(' ', $joins);

    if (!empty($this->filter)) {
      $sql .= ' WHERE ' . implode(', ', $this->filter);
    }

    $sql .= ' GROUP BY ' . $this->definition['field'];

    // Create the join (full SQL) ----------------
    $output[] = $this->create_single_join(
      $query,
      array(
        'table' => $this->definition['table'],
        'field' => $this->definition['field'],
        'table_sql' => $sql,
        'is_drupal' => FALSE,
      ),
      array(
        'table' => $this->definition['left_table'],
        'field' => $this->definition['left_field'],
      ),
      'LEFT'
    );

    return implode("\n", $output);
  }

  /**
   * Creates SQL for a single join based on parameters
   * Join will be: <type> JOIN (<query creating one-to-one table using array_agg>) <table alias>
   *                  ON <qualified left field>=<qualified right field>
   */
  function create_single_join(&$query, $right_spec, $left_spec, $join_type) {

    if ($right_spec['table']) {
      $right = $query->get_table_info($right_spec['table']);
      if (!$right['alias']) {
        $right['alias'] = $right_spec['table'];
      }
      $right_field = "$right[alias].$right_spec[field]";

      if ($right_spec['is_drupal']) {
        $right_table = '{' . $right_spec['table'] . '}';
      }
      else {
        $right_table = $right_spec['table'];
      }
    }

    if ($left_spec['table']) {
      $left = $query->get_table_info($left_spec['table']);
      if (!$left['alias']) {
        $left['alias'] = $left_spec['table'];
      }
      $left_field = "$left[alias].$left_spec[field]";
    }
    else {
      // This can be used if left_field is a formula or something. It should be used only *very* rarely.
      $left_field = $this->left_spec['field'];
    }

    $output = " $join_type JOIN ($right_spec[table_sql]) $right[alias] ON $left_field = $right_field";

    return $output;
  }

}