class UpdateQuery_sqlsrv in Drupal driver for SQL Server and SQL Azure 7

SQL Server-specific implementation of UPDATE.

The specific parts are:

• SQL Server returns the number of matched rows to an UPDATE, and Drupal requires the number of affected rows to be returned.
• SQL Server requires a special handling for the blobs.

Hierarchy

• class \Query implements QueryPlaceholderInterface
  • class \UpdateQuery implements QueryConditionInterface
    • class \UpdateQuery_sqlsrv

File

sqlsrv/query.inc, line 157

class UpdateQuery_sqlsrv extends UpdateQuery {

  /**
   * Rewrite the query not to select non-affected 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')
   */
  protected function excludeNonAffectedRows() {
    if (!empty($this->queryOptions['sqlsrv_return_matched_rows'])) {
      return;
    }

    // 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.
        // Re-bind the placeholders.
        $expression = $data['expression'];
        $arguments = array();
        if (!empty($data['arguments'])) {
          foreach ($data['arguments'] as $placeholder => $value) {
            $new_placeholder = ':db_exclude_placeholder_' . $this
              ->nextPlaceholder();
            $expression = str_replace($placeholder, $new_placeholder, $expression);
            $arguments[$new_placeholder] = $value;
          }
        }
        $condition
          ->where($field . ' <> ' . $expression, $arguments);
        $condition
          ->isNull($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)) {

      // Workaround for a bug in the base MergeQuery implementation:
      // a DatabaseCondition object is reused without being re-compiled,
      // leading to duplicate placeholders.
      $this->nextPlaceholder = 1000000;
      $this
        ->condition($condition);
    }
  }
  public function execute() {

    // Rewrite the query to exclude the non-affected rows.
    $this
      ->excludeNonAffectedRows();

    // Now perform the special handling for BLOB fields.
    $max_placeholder = 0;

    // Because we filter $fields the same way here and in __toString(), the
    // placeholders will all match up properly.
    $stmt = $this->connection
      ->PDOPrepare($this->connection
      ->prefixTables((string) $this));

    // Fetch the list of blobs and sequences used on that table.
    $columnInformation = $this->connection
      ->schema()
      ->queryColumnInformation($this->table);

    // Expressions take priority over literal fields, so we process those first
    // and remove any literal fields that conflict.
    $fields = $this->fields;
    $expression_fields = array();
    foreach ($this->expressionFields as $field => $data) {
      if (!empty($data['arguments'])) {
        foreach ($data['arguments'] as $placeholder => $argument) {

          // We assume that an expression will never happen on a BLOB field,
          // which is a fairly safe assumption to make since in most cases
          // it would be an invalid query anyway.
          $stmt
            ->bindParam($placeholder, $data['arguments'][$placeholder]);
        }
      }
      unset($fields[$field]);
    }

    // We use this array to store references to the blob handles.
    // This is necessary because the PDO will otherwise messes up with references.
    $blobs = array();
    $blob_count = 0;
    foreach ($fields as $field => $value) {
      $placeholder = ':db_update_placeholder_' . $max_placeholder++;
      if (isset($columnInformation['blobs'][$field])) {
        $blobs[$blob_count] = fopen('php://memory', 'a');
        fwrite($blobs[$blob_count], $value);
        rewind($blobs[$blob_count]);
        $stmt
          ->bindParam($placeholder, $blobs[$blob_count], PDO::PARAM_LOB, 0, PDO::SQLSRV_ENCODING_BINARY);
        $blob_count++;
      }
      else {
        $stmt
          ->bindParam($placeholder, $fields[$field]);
      }
    }
    if (count($this->condition)) {
      $this->condition
        ->compile($this->connection, $this);
      $arguments = $this->condition
        ->arguments();
      foreach ($arguments as $placeholder => $value) {
        $stmt
          ->bindParam($placeholder, $arguments[$placeholder]);
      }
    }
    $options = $this->queryOptions;
    $options['already_prepared'] = TRUE;
    $stmt
      ->execute();
    return $stmt
      ->rowCount();
  }
  public function __toString() {

    // Create a sanitized comment string to prepend to the query.
    $prefix = $this->connection
      ->makeComment($this->comments);

    // Expressions take priority over literal fields, so we process those first
    // and remove any literal fields that conflict.
    $fields = $this->fields;
    $update_fields = array();
    foreach ($this->expressionFields as $field => $data) {
      $update_fields[] = $this->connection
        ->quoteIdentifier($field) . '=' . $data['expression'];
      unset($fields[$field]);
    }
    $max_placeholder = 0;
    foreach ($fields as $field => $value) {
      $update_fields[] = $this->connection
        ->quoteIdentifier($field) . '=:db_update_placeholder_' . $max_placeholder++;
    }
    $query = $prefix . 'UPDATE {' . $this->connection
      ->escapeTable($this->table) . '} SET ' . implode(', ', $update_fields);
    if (count($this->condition)) {
      $this->condition
        ->compile($this->connection, $this);

      // There is an implicit string cast on $this->condition.
      $query .= "\nWHERE " . $this->condition;
    }
    return $query;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Query::$comments	protected	property	An array of comments that can be prepended to a query.
Query::$connection	protected	property	The connection object on which to run this query.
Query::$connectionKey	protected	property	The key of the connection object.
Query::$connectionTarget	protected	property	The target of the connection object.
Query::$nextPlaceholder	protected	property	The placeholder counter.
Query::$queryOptions	protected	property	The query options to pass on to the connection object.
Query::$uniqueIdentifier	protected	property	A unique identifier for this query object.
Query::comment	public	function	Adds a comment to the query.
Query::getComments	public	function	Returns a reference to the comments array for the query.
Query::nextPlaceholder	public	function	Gets the next placeholder value for this query object. Overrides QueryPlaceholderInterface::nextPlaceholder
Query::uniqueIdentifier	public	function	Returns a unique identifier for this object. Overrides QueryPlaceholderInterface::uniqueIdentifier
Query::__clone	public	function	Implements the magic __clone function.	1
Query::__sleep	public	function	Implements the magic __sleep function to disconnect from the database.
Query::__wakeup	public	function	Implements the magic __wakeup function to reconnect to the database.
UpdateQuery::$arguments	protected	property	An array of values to update to.
UpdateQuery::$condition	protected	property	The condition object for this query.
UpdateQuery::$expressionFields	protected	property	Array of fields to update to an expression in case of a duplicate record.
UpdateQuery::$fields	protected	property	An array of fields that will be updated.
UpdateQuery::$table	protected	property	The table to update.
UpdateQuery::arguments	public	function	Implements QueryConditionInterface::arguments(). Overrides QueryConditionInterface::arguments
UpdateQuery::compile	public	function	Implements QueryConditionInterface::compile(). Overrides QueryConditionInterface::compile
UpdateQuery::compiled	public	function	Implements QueryConditionInterface::compiled(). Overrides QueryConditionInterface::compiled
UpdateQuery::condition	public	function	Implements QueryConditionInterface::condition(). Overrides QueryConditionInterface::condition
UpdateQuery::conditions	public	function	Implements QueryConditionInterface::conditions(). Overrides QueryConditionInterface::conditions
UpdateQuery::exists	public	function	Implements QueryConditionInterface::exists(). Overrides QueryConditionInterface::exists
UpdateQuery::expression	public	function	Specifies fields to be updated as an expression.
UpdateQuery::fields	public	function	Adds a set of field->value pairs to be updated.
UpdateQuery::isNotNull	public	function	Implements QueryConditionInterface::isNotNull(). Overrides QueryConditionInterface::isNotNull
UpdateQuery::isNull	public	function	Implements QueryConditionInterface::isNull(). Overrides QueryConditionInterface::isNull
UpdateQuery::notExists	public	function	Implements QueryConditionInterface::notExists(). Overrides QueryConditionInterface::notExists
UpdateQuery::where	public	function	Implements QueryConditionInterface::where(). Overrides QueryConditionInterface::where
UpdateQuery::__construct	public	function	Constructs an UpdateQuery object. Overrides Query::__construct
UpdateQuery_sqlsrv::excludeNonAffectedRows	protected	function	Rewrite the query not to select non-affected rows.
UpdateQuery_sqlsrv::execute	public	function	Executes the UPDATE query. Overrides UpdateQuery::execute
UpdateQuery_sqlsrv::__toString	public	function	Implements PHP magic __toString method to convert the query to a string. Overrides UpdateQuery::__toString