- [feature] Added "no_parameters=True" execution

    option for connections.   If no parameters
    are present, will pass the statement
    as cursor.execute(statement), thereby invoking
    the DBAPIs behavior when no parameter collection
    is present; for psycopg2 and mysql-python, this
    means not interpreting % signs in the string.
    This only occurs with this option, and not
    just if the param list is blank, as otherwise
    this would produce inconsistent behavior
    of SQL expressions that normally escape percent
    signs (and while compiling, can't know ahead of
    time if parameters will be present in
    some cases).  [ticket:2407]

1 files changed, 32 insertions, 5 deletions

diff --git a/lib/sqlalchemy/engine/base.py b/lib/sqlalchemy/engine/base.py
index 0224d0843..7cc5522c4 100644
--- a/lib/sqlalchemy/engine/base.py
+++ b/lib/sqlalchemy/engine/base.py
@@ -491,14 +491,23 @@ class Dialect(object):
         raise NotImplementedError()
 
     def do_executemany(self, cursor, statement, parameters, context=None):
-        """Provide an implementation of *cursor.executemany(statement,
-        parameters)*."""
+        """Provide an implementation of ``cursor.executemany(statement,
+        parameters)``."""
 
         raise NotImplementedError()
 
     def do_execute(self, cursor, statement, parameters, context=None):
-        """Provide an implementation of *cursor.execute(statement,
-        parameters)*."""
+        """Provide an implementation of ``cursor.execute(statement,
+        parameters)``."""
+
+        raise NotImplementedError()
+
+    def do_execute_no_params(self, cursor, statement, parameters, context=None):
+        """Provide an implementation of ``cursor.execute(statement)``.
+
+        The parameter collection should not be sent.
+
+        """
 
         raise NotImplementedError()
 
@@ -976,6 +985,18 @@ class Connection(Connectable):
           is returned to the connection pool, i.e.
           the :meth:`.Connection.close` method is called.
 
+        :param no_parameters: When ``True``, if the final parameter 
+          list or dictionary is totally empty, will invoke the 
+          statement on the cursor as ``cursor.execute(statement)``,
+          not passing the parameter collection at all.
+          Some DBAPIs such as psycopg2 and mysql-python consider
+          percent signs as significant only when parameters are 
+          present; this option allows code to generate SQL
+          containing percent signs (and possibly other characters)
+          that is neutral regarding whether it's executed by the DBAPI
+          or piped into a script that's later invoked by 
+          command line tools.  New in 0.7.6.
+          
         :param stream_results: Available on: Connection, statement.
           Indicate to the dialect that results should be 
           "streamed" and not pre-buffered, if possible.  This is a limitation
@@ -1647,7 +1668,8 @@ class Connection(Connectable):
 
         if self._echo:
             self.engine.logger.info(statement)
-            self.engine.logger.info("%r", sql_util._repr_params(parameters, batches=10))
+            self.engine.logger.info("%r", 
+                    sql_util._repr_params(parameters, batches=10))
         try:
             if context.executemany:
                 self.dialect.do_executemany(
@@ -1655,6 +1677,11 @@ class Connection(Connectable):
                                     statement, 
                                     parameters, 
                                     context)
+            elif not parameters and context.no_parameters:
+                self.dialect.do_execute_no_params(
+                                    cursor, 
+                                    statement, 
+                                    context)
             else:
                 self.dialect.do_execute(
                                     cursor,