<?php

/**

 * @file

 * Query code for SQLite embedded database engine.

 */

/**

 * @addtogroup database

 * @{

 */

/**

 * SQLite specific implementation of InsertQuery.

 *

 * We ignore all the default fields and use the clever SQLite syntax:

 *   INSERT INTO table DEFAULT VALUES

 * for degenerated "default only" queries.

 */

class InsertQuery_sqlite extends InsertQuery {

  public function execute() {

    if (!$this->preExecute()) {

      return NULL;

    }

    if (count($this->insertFields)) {

      return parent::execute();

    }

    else {

      return $this->connection->query('INSERT INTO {' . $this->table . '} DEFAULT VALUES', array(), $this->queryOptions);

    }

  }

  public function __toString() {

    // Create a sanitized comment string to prepend to the query.

    $comments = $this->connection->makeComment($this->comments);

    // Produce as many generic placeholders as necessary.

    $placeholders = array_fill(0, count($this->insertFields), '?');

    // If we're selecting from a SelectQuery, finish building the query and

    // pass it back, as any remaining options are irrelevant.

    if (!empty($this->fromQuery)) {

      $insert_fields_string = $this->insertFields ? ' (' . implode(', ', $this->insertFields) . ') ' : ' ';

      return $comments . 'INSERT INTO {' . $this->table . '}' . $insert_fields_string . $this->fromQuery;

    }

    return $comments . 'INSERT INTO {' . $this->table . '} (' . implode(', ', $this->insertFields) . ') VALUES (' . implode(', ', $placeholders) . ')';

  }

}

/**

 * SQLite specific implementation of UpdateQuery.

 *

 * SQLite counts all the rows that match the conditions as modified, even if they

 * will not be affected by the query. We workaround this by ensuring that

 * we don't select those rows.

 *

 * A query like this one:

 *   UPDATE test SET col1 = 'newcol1', col2 = 'newcol2' WHERE tid = 1

 * will become:

 *   UPDATE test SET col1 = 'newcol1', col2 = 'newcol2' WHERE tid = 1 AND (col1 <> 'newcol1' OR col2 <> 'newcol2')

 */

class UpdateQuery_sqlite extends UpdateQuery {

  public function execute() {

    if (!empty($this->queryOptions['sqlite_return_matched_rows'])) {

      return parent::execute();

    }

    // Get the fields used in the update query.

    $fields = $this->expressionFields + $this->fields;

    // Add the inverse of the fields to the condition.

    $condition = new DatabaseCondition('OR');

    foreach ($fields as $field => $data) {

      if (is_array($data)) {

        // The field is an expression.

        $condition->where($field . ' <> ' . $data['expression']);

        $condition->isNull($field);

      }

      elseif (!isset($data)) {

        // The field will be set to NULL.

        $condition->isNotNull($field);

      }

      else {

        $condition->condition($field, $data, '<>');

        $condition->isNull($field);

      }

    }

    if (count($condition)) {

      $condition->compile($this->connection, $this);

      $this->condition->where((string) $condition, $condition->arguments());

    }

    return parent::execute();

  }

}

/**

 * SQLite specific implementation of DeleteQuery.

 */

class DeleteQuery_sqlite extends DeleteQuery {

  public function execute() {

    // When the WHERE is omitted from a DELETE statement and the table being

    // deleted has no triggers, SQLite uses an optimization to erase the entire

    // table content without having to visit each row of the table individually.

    // Prior to SQLite 3.6.5, SQLite does not return the actual number of rows

    // deleted by that optimized "truncate" optimization. But we want to return

    // the number of rows affected, so we calculate it directly.

    if (!count($this->condition)) {

      $total_rows = $this->connection->query('SELECT COUNT(*) FROM {' . $this->connection->escapeTable($this->table) . '}')->fetchField();

      parent::execute();

      return $total_rows;

    }

    else {

      return parent::execute();

    }

  }

}

/**

 * SQLite specific implementation of TruncateQuery.

 *

 * SQLite doesn't support TRUNCATE, but a DELETE query with no condition has

 * exactly the effect (it is implemented by DROPing the table).

 */

class TruncateQuery_sqlite extends TruncateQuery {

  public function __toString() {

    // Create a sanitized comment string to prepend to the query.

    $comments = $this->connection->makeComment($this->comments);

    return $comments . 'DELETE FROM {' . $this->connection->escapeTable($this->table) . '} ';

  }

}

/**

 * @} End of "addtogroup database".

 */