cast converted into its own ClauseElement so that it can have an explicit compilation

function in ANSICompiler
MySQLCompiler then skips most CAST calls since it only seems to support the standard syntax for Date
types; other types now a TODO for MySQL
then, polymorphic_union() function now CASTs null()s to the type corresponding to the columns in the UNION,
since postgres doesnt like mixing NULL with integer types
(long road for that .....)

diff --git a/CHANGES b/CHANGES
index 9b80778efacfb9971bafd01e85683f431bafc92c..5bcbda4d737cb209e9cf13b7e0886601efeea586 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -40,6 +40,11 @@ function at the moment
 information better [ticket:202]
 - if an object fails to be constructed, is not added to the 
 session [ticket:203]
+- CAST function has been made into its own clause object with
+its own compilation function in ansicompiler; allows MySQL
+to silently ignore most CAST calls since MySQL
+seems to only support the standard CAST syntax with Date types.  
+MySQL-compatible CAST support for strings, ints, etc. a TODO
 
 0.2.2
 - big improvements to polymorphic inheritance behavior, enabling it

diff --git a/lib/sqlalchemy/ansisql.py b/lib/sqlalchemy/ansisql.py
index cdd86044021448a492a8afc8e01799528bbb4b41..82abb95775ebf285b4d001bb13dbd062290cec95 100644 (file)
--- a/lib/sqlalchemy/ansisql.py
+++ b/lib/sqlalchemy/ansisql.py
@@ -231,7 +231,13 @@ class ANSICompiler(sql.Compiled):
             self.strings[list] = "(" + string.join([self.get_str(c) for c in list.clauses], ' ') + ")"
         else:
             self.strings[list] = string.join([self.get_str(c) for c in list.clauses], ' ')
-       
+      
+    def visit_cast(self, cast):
+        if len(self.select_stack):
+            # not sure if we want to set the typemap here...
+            self.typemap.setdefault("CAST", cast.type)
+        self.strings[cast] = "CAST(%s AS %s)" % (self.strings[cast.clause],self.strings[cast.typeclause])
+         
     def visit_function(self, func):
         if len(self.select_stack):
             self.typemap.setdefault(func.name, func.type)

diff --git a/lib/sqlalchemy/databases/mysql.py b/lib/sqlalchemy/databases/mysql.py
index aa05134d0416dcbad644daad820709eb038b42da..e32d6f120a470bbf2096af26fed35656ee0edde0 100644 (file)
--- a/lib/sqlalchemy/databases/mysql.py
+++ b/lib/sqlalchemy/databases/mysql.py
@@ -9,7 +9,6 @@ import sys, StringIO, string, types, re, datetime
 from sqlalchemy import sql,engine,schema,ansisql
 from sqlalchemy.engine import default
 import sqlalchemy.types as sqltypes
-import sqlalchemy.databases.information_schema as ischema
 import sqlalchemy.exceptions as exceptions
 
 try:
@@ -250,6 +249,15 @@ class MySQLDialect(ansisql.ANSIDialect):
 
 class MySQLCompiler(ansisql.ANSICompiler):
 
+    def visit_cast(self, cast):
+        """hey ho MySQL supports almost no types at all for CAST"""
+        if (isinstance(cast.type, sqltypes.Date) or isinstance(cast.type, sqltypes.Time) or isinstance(cast.type, sqltypes.DateTime)):
+            return super(MySQLCompiler, self).visit_cast(cast)
+        else:
+            # so just skip the CAST altogether for now.
+            # TODO: put whatever MySQL does for CAST here.
+            self.strings[cast] = self.strings[cast.clause]
+
     def limit_clause(self, select):
         text = ""
         if select.limit is not None:

diff --git a/lib/sqlalchemy/orm/util.py b/lib/sqlalchemy/orm/util.py
index 86799b31166e25d67dab1a4091cc14ee9698b5f5..10f7b4e808d542aa2cd7ea0e6e2ee70ccd23771a 100644 (file)
--- a/lib/sqlalchemy/orm/util.py
+++ b/lib/sqlalchemy/orm/util.py
@@ -24,7 +24,7 @@ class CascadeOptions(object):
 def polymorphic_union(table_map, typecolname, aliasname='p_union'):
     colnames = util.Set()
     colnamemaps = {}
-    
+    types = {}
     for key in table_map.keys():
         table = table_map[key]
 
@@ -37,13 +37,14 @@ def polymorphic_union(table_map, typecolname, aliasname='p_union'):
         for c in table.c:
             colnames.add(c.name)
             m[c.name] = c
+            types[c.name] = c.type
         colnamemaps[table] = m
         
     def col(name, table):
         try:
             return colnamemaps[table][name]
         except KeyError:
-            return sql.null().label(name)
+            return sql.cast(sql.null(), types[name]).label(name)
 
     result = []
     for type, table in table_map.iteritems():

diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index 0cacea12d0cf115af8d0ff1106a0c33b7cbfa6fd..d978ee208ee8156c9954e17217a9894dc0160617 100644 (file)
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -153,12 +153,9 @@ def cast(clause, totype, **kwargs):
          or
         cast(table.c.timestamp, DATE)
     """
-    # handle non-column clauses (e.g. cast(1234, TEXT)
-    if not hasattr(clause, 'label'):
-        clause = literal(clause)
-    totype = sqltypes.to_instance(totype)
-    return Function('CAST', CompoundClause("AS", clause, TypeClause(totype)), type=totype, **kwargs)
-        
+    return Cast(clause, totype, **kwargs)
+
+
 def exists(*args, **params):
     params['correlate'] = True
     s = select(*args, **params)
@@ -320,6 +317,7 @@ class ClauseVisitor(object):
     def visit_clauselist(self, list):pass
     def visit_calculatedclause(self, calcclause):pass
     def visit_function(self, func):pass
+    def visit_cast(self, cast):pass
     def visit_label(self, label):pass
     def visit_typeclause(self, typeclause):pass
             
@@ -974,7 +972,20 @@ class Function(CalculatedClause):
             c.accept_visitor(visitor)
         visitor.visit_function(self)
 
-
+class Cast(ColumnElement):
+    def __init__(self, clause, totype, **kwargs):
+        if not hasattr(clause, 'label'):
+            clause = literal(clause)
+        self.type = sqltypes.to_instance(totype)
+        self.clause = clause
+        self.typeclause = TypeClause(self.type)
+    def accept_visitor(self, visitor):
+        self.clause.accept_visitor(visitor)
+        self.typeclause.accept_visitor(visitor)
+        visitor.visit_cast(self)
+    def _get_from_objects(self):
+        return self.clause._get_from_objects()
+        
 class FunctionGenerator(object):
     """generates Function objects based on getattr calls"""
     def __init__(self, engine=None):

diff --git a/test/sql/select.py b/test/sql/select.py
index 290e324cf2cd75013348b05ac2d88c4bb3630269..d78f36b1add2aea346e98b9cd9db2a029400af9d 100644 (file)
--- a/test/sql/select.py
+++ b/test/sql/select.py
@@ -556,14 +556,14 @@ FROM mytable, myothertable WHERE mytable.myid = myothertable.otherid AND mytable
         check_results(postgres.dialect(), ['NUMERIC(10, 2)', 'NUMERIC(12, 9)', 'DATE', 'TEXT', 'VARCHAR(20)'], '%(literal)s')
 
         # then the Oracle engine
-#        check_results(oracle.OracleDialect(), ['NUMERIC(10, 2)', 'NUMERIC(12, 9)', 'DATE', 'CLOB', 'VARCHAR(20)'], ':literal')
+        check_results(oracle.dialect(), ['NUMERIC(10, 2)', 'NUMERIC(12, 9)', 'DATE', 'CLOB', 'VARCHAR(20)'], ':literal')
 
         # then the sqlite engine
         check_results(sqlite.dialect(), ['NUMERIC(10, 2)', 'NUMERIC(12, 9)', 'DATE', 'TEXT', 'VARCHAR(20)'], '?')
 
-        # and the MySQL engine
-        check_results(mysql.dialect(), ['NUMERIC(10, 2)', 'NUMERIC(12, 9)', 'DATE', 'TEXT', 'VARCHAR(20)'], '%s')
-
+        # MySQL seems to only support DATE types for cast
+        self.assertEqual(str(cast(tbl.c.ts, Date).compile(dialect=mysql.dialect())), 'CAST(casttest.ts AS DATE)')
+        self.assertEqual(str(cast(tbl.c.ts, Numeric).compile(dialect=mysql.dialect())), 'casttest.ts')
 
     def testdatebetween(self):
         import datetime