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   1. drupal7

Verwandte Themen

Database abstraction layer

Allow the use of different database servers using the same code base.

Code

includes/database/select.inc, line 1058

<?php
public function __toString() {

  // SELECT
  $query = 'SELECT ';
  if ($this->distinct) {
    $query .= 'DISTINCT ';
  }

  // FIELDS and EXPRESSIONS
  $fields = array();
  foreach ($this->fields as $alias => $field) {
    // Always use the AS keyword for field aliases, as some
    // databases require it (e.g., PostgreSQL).
    $fields[] = (isset($field['table']) ? $field['table'] . '.' : '') . $field['field'] . ' AS ' . $field['alias'];
  }
  foreach ($this->expressions as $alias => $expression) {
    $fields[] = $expression['expression'] . ' AS ' . $expression['alias'];
  }
  foreach ($this->tables as $alias => $table) {
    if (!empty($table['all_fields'])) {
      $fields[] = $alias . '.*';
    }
  }
  $query .= implode(', ', $fields);


  // FROM - We presume all queries have a FROM, as any query that doesn't won't need the query builder anyway.
  $query .= "\nFROM ";
  foreach ($this->tables as $alias => $table) {
    $query .= "\n";
    if (isset($table['join type'])) {
      $query .= $table['join type'] . ' JOIN ';
    }

    // If the table is a subquery, compile it and integrate it into this query.
    if ($table['table'] instanceof SelectQueryInterface) {
      $table_string = '(' . (string) $table['table'] . ')';
    }
    else {
      $table_string = '{' . $this->connection->escapeTable($table['table']) . '}';
    }

    // Don't use the AS keyword for table aliases, as some
    // databases don't support it (e.g., Oracle).
    $query .=  $table_string . ' ' . $table['alias'];

    if (!empty($table['condition'])) {
      $query .= ' ON ' . $table['condition'];
    }
  }

  // WHERE
  if (count($this->where)) {
    $this->where->compile($this->connection);
    // There is an implicit string cast on $this->condition.
    $query .= "\nWHERE " . $this->where;
  }

  // GROUP BY
  if ($this->group) {
    $query .= "\nGROUP BY " . implode(', ', $this->group);
  }

  // HAVING
  if (count($this->having)) {
    $this->having->compile($this->connection);
    // There is an implicit string cast on $this->having.
    $query .= "\nHAVING " . $this->having;
  }

  // ORDER BY
  if ($this->order) {
    $query .= "\nORDER BY ";
    $fields = array();
    foreach ($this->order as $field => $direction) {
      $fields[] = $field . ' ' . $direction;
    }
    $query .= implode(', ', $fields);
  }

  // RANGE is database specific, so we can't do it here.

  return $query;
}
?>