3 files changed, 88 insertions, 0 deletions
diff --git a/includes/database/database.inc b/includes/database/database.inc
index f07e07373..60d4b415f 100644
--- a/includes/database/database.inc
+++ b/includes/database/database.inc
@@ -255,6 +255,13 @@ abstract class DatabaseConnection extends PDO {
   protected $deleteClass = NULL;
 
   /**
+   * The name of the Truncate class for this connection.
+   *
+   * @var string
+   */
+  protected $truncateClass = NULL;
+
+  /**
    * The name of the Insert class for this connection.
    *
    * @var string
@@ -763,6 +770,26 @@ abstract class DatabaseConnection extends PDO {
   }
 
   /**
+   * Prepare and return a TRUNCATE query object.
+   *
+   * @see TruncateQuery
+   * @param $options
+   *   An array of options on the query.
+   * @return
+   *   A new DeleteQuery object.
+   */
+  public function truncate($table, array $options = array()) {
+    if (empty($this->truncateClass)) {
+      $this->truncateClass = 'TruncateQuery_' . $this->driver();
+      if (!class_exists($this->truncateClass)) {
+        $this->truncateClass = 'TruncateQuery';
+      }
+    }
+    $class = $this->truncateClass;
+    return new $class($this, $table, $options);
+  }
+
+  /**
    * Returns a DatabaseSchema object for manipulating the schema of this database.
    *
    * This method will lazy-load the appropriate schema library file.
@@ -1881,6 +1908,23 @@ function db_delete($table, array $options = array()) {
 }
 
 /**
+ * Returns a new TruncateQuery object for the active database.
+ *
+ * @param $table
+ *   The table from which to delete.
+ * @param $options
+ *   An array of options to control how the query operates.
+ * @return
+ *   A new TruncateQuery object for this connection.
+ */
+function db_truncate($table, array $options = array()) {
+  if (empty($options['target']) || $options['target'] == 'slave') {
+    $options['target'] = 'default';
+  }
+  return Database::getConnection($options['target'])->truncate($table, $options);
+}
+
+/**
  * Returns a new SelectQuery object for the active database.
  *
  * @param $table
diff --git a/includes/database/query.inc b/includes/database/query.inc
index 8c7281820..8cdaaf5e1 100644
--- a/includes/database/query.inc
+++ b/includes/database/query.inc
@@ -829,6 +829,38 @@ class DeleteQuery extends Query implements QueryConditionInterface {
   }
 }
 
+
+/**
+ * General class for an abstracted TRUNCATE operation.
+ */
+class TruncateQuery extends Query {
+
+  /**
+   * The table from which to delete.
+   *
+   * @var string
+   */
+  protected $table;
+
+  public function __construct(DatabaseConnection $connection, $table, array $options = array()) {
+    $options['return'] = Database::RETURN_AFFECTED;
+    parent::__construct($connection, $options);
+    $this->table = $table;
+  }
+
+  public function compile(DatabaseConnection $connection) {
+    return $this->condition->compile($connection);
+  }
+
+  public function execute() {
+    return $this->connection->query((string)$this, array(), $this->queryOptions);
+  }
+
+  public function __toString() {
+    return 'TRUNCATE {' . $this->connection->escapeTable($this->table) . '} ';
+  }
+}
+
 /**
  * General class for an abstracted UPDATE operation.
  */
diff --git a/includes/database/sqlite/query.inc b/includes/database/sqlite/query.inc
index ab6e2da50..98fa80754 100644
--- a/includes/database/sqlite/query.inc
+++ b/includes/database/sqlite/query.inc
@@ -136,5 +136,17 @@ class DeleteQuery_sqlite extends DeleteQuery {
 }
 
 /**
+ * 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() {
+    return 'DELETE FROM {' . $this->connection->escapeTable($this->table) . '} ';
+  }
+}
+
+/**
  * @} End of "ingroup database".
  */