some enhancemnets to unions, unions and selects need to be more commonly derived,

also more tweaks to mapper eager query compilation involving distinct etc.

diff --git a/lib/sqlalchemy/ansisql.py b/lib/sqlalchemy/ansisql.py
index 79215dec7a40526e2e4b211b9f8d3d23b0e03316..28003047a52ed8db0313fd40b7391a4da9892a4c 100644 (file)
--- a/lib/sqlalchemy/ansisql.py
+++ b/lib/sqlalchemy/ansisql.py
@@ -165,10 +165,11 @@ class ANSICompiler(sql.Compiled):
         else:
             sep = " " + compound.operator + " "
         
+        s = string.join([self.get_str(c) for c in compound.clauses], sep)
         if compound.parens:
-            self.strings[compound] = "(" + string.join([self.get_str(c) for c in compound.clauses], sep) + ")"
+            self.strings[compound] = "(" + s + ")"
         else:
-            self.strings[compound] = string.join([self.get_str(c) for c in compound.clauses], sep)
+            self.strings[compound] = s
         
     def visit_clauselist(self, list):
         if list.parens:
@@ -184,6 +185,8 @@ class ANSICompiler(sql.Compiled):
         for tup in cs.clauses:
             text += " " + tup[0] + " " + self.get_str(tup[1])
         self.strings[cs] = text
+        self.froms[cs] = "(" + text + ")"
+        print "cs from text:" + self.froms[cs]
             
     def visit_binary(self, binary):
         result = self.get_str(binary.left)
@@ -276,8 +279,10 @@ class ANSICompiler(sql.Compiled):
             text += self.limit_clause(select)
             
         if getattr(select, 'issubquery', False):
+            print "subquery"
             self.strings[select] = "(" + text + ")"
         else:
+            print "not a subquery"
             self.strings[select] = text
 
         self.froms[select] = "(" + text + ")"

diff --git a/lib/sqlalchemy/mapping/mapper.py b/lib/sqlalchemy/mapping/mapper.py
index 2860cff7ccbd5b37c32e0c61ca5d5786132ac53e..05cfcd349ee4d43e052c7e288663f0f836785063 100644 (file)
--- a/lib/sqlalchemy/mapping/mapper.py
+++ b/lib/sqlalchemy/mapping/mapper.py
@@ -306,7 +306,7 @@ class Mapper(object):
         will be executed and its resulting rowset used to build new object instances.  
         in this case, the developer must insure that an adequate set of columns exists in the 
         rowset with which to build new object instances."""
-        if arg is not None and isinstance(arg, sql.Select):
+        if arg is not None and isinstance(arg, sql.Selectable):
             return self.select_statement(arg, **kwargs)
         else:
             return self.select_whereclause(arg, **kwargs)
@@ -444,26 +444,38 @@ class Mapper(object):
     def register_deleted(self, obj, uow):
         for prop in self.props.values():
             prop.register_deleted(obj, uow)
-            
+    
+    def _should_nest(self, **kwargs):
+        """returns True if the given statement options indicate that we should "nest" the
+        generated query as a subquery inside of a larger eager-loading query.  this is used
+        with keywords like distinct, limit and offset and the mapper defines eager loads."""
+        return (
+            getattr(self, '_has_eager', False)
+            and (kwargs.has_key('limit') or kwargs.has_key('offset') or kwargs.get('distinct', True))
+        )
+        
     def _compile(self, whereclause = None, **kwargs):
-        if getattr(self, '_has_eager', False) and (kwargs.has_key('limit') or kwargs.has_key('offset')):
-            s2 = sql.select(self.table.primary_key, whereclause, **kwargs)
-            s2.order_by(self.table.rowid_column)
+        if self._should_nest(**kwargs):
+            s2 = sql.select(self.table.primary_key, whereclause, use_labels=True, **kwargs)
+            if not kwargs.get('distinct', True):
+                s2.order_by(self.table.rowid_column)
             s3 = s2.alias('rowcount')
             crit = []
             for i in range(0, len(self.table.primary_key)):
                 crit.append(s3.primary_key[i] == self.table.primary_key[i])
-            statement = sql.select([self.table], sql.and_(*crit))
+            statement = sql.select([self.table], sql.and_(*crit), use_labels=True)
             if kwargs.has_key('order_by'):
-                statement.order_by(kwargs['order_by'])
+                statement.order_by(*kwargs['order_by'])
             statement.order_by(self.table.rowid_column)
         else:
-            statement = sql.select([self.table], whereclause, **kwargs)
-            statement.order_by(self.table.rowid_column)
+            statement = sql.select([self.table], whereclause, use_labels=True, **kwargs)
+            if not kwargs.get('distinct', True):
+                statement.order_by(self.table.rowid_column)
         # plugin point
+        
+        # give all the attached properties a chance to modify the query
         for key, value in self.props.iteritems():
             value.setup(key, statement, **kwargs) 
-        statement.use_labels = True
         return statement
 
     def _identity_key(self, row):

diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index 10e8f3e74c07392e9c7c609fa67554551f0ed437..26c9a862be630f24972aedeec499a2ab5f30a8ce 100644 (file)
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -907,6 +907,12 @@ class TailClauseMixin(object):
     def group_by(self, *clauses):
         self._append_clause('group_by_clause', "GROUP BY", *clauses)
     def _append_clause(self, attribute, prefix, *clauses):
+        if len(clauses) == 1 and clauses[0] is None:
+            try:
+                delattr(self, attribute)
+            except AttributeError:
+                pass
+            return
         if not hasattr(self, attribute):
             l = ClauseList(*clauses)
             setattr(self, attribute, l)
@@ -920,8 +926,14 @@ class TailClauseMixin(object):
             
 class CompoundSelect(Selectable, TailClauseMixin):
     def __init__(self, keyword, *selects, **kwargs):
+        self.id = "Compound(%d)" % id(self)
         self.keyword = keyword
         self.selects = selects
+        self.use_labels = kwargs.pop('use_labels', False)
+        self.rowid_column = selects[0].rowid_column
+        for s in self.selects:
+            s.order_by(None)
+            s.group_by(None)
         self.clauses = []
         order_by = kwargs.get('order_by', None)
         if order_by:
@@ -944,7 +956,9 @@ class CompoundSelect(Selectable, TailClauseMixin):
                 return e
         else:
             return None
-        
+    def _get_from_objects(self):
+        return [self]
+       
 class Select(Selectable, TailClauseMixin):
     """finally, represents a SELECT statement, with appendable clauses, as well as 
     the ability to execute itself and return a result set."""