- column labels are now generated in the compilation phase, which

means their lengths are dialect-dependent.  So on oracle a label
that gets truncated to 30 chars will go out to 63 characters
on postgres.  Also, the true labelname is always attached as the
accessor on the parent Selectable so theres no need to be aware
of the genrerated label names [ticket:512].
- ResultProxy column targeting is greatly simplified, and relies
upon the ANSICompiler's column_labels map to translate the built-in
label on a _ColumnClause (which is now considered to be a unique
identifier of that column) to the label which was generated at compile
time.
- still need to put a baseline of ColumnClause targeting for
ResultProxy objects that originated from a textual query.

1 files changed, 15 insertions, 9 deletions

diff --git a/lib/sqlalchemy/ansisql.py b/lib/sqlalchemy/ansisql.py
index ebaedca54..0d4fba4e8 100644
--- a/lib/sqlalchemy/ansisql.py
+++ b/lib/sqlalchemy/ansisql.py
@@ -12,7 +12,7 @@ module.
 
 from sqlalchemy import schema, sql, engine, util, sql_util, exceptions
 from  sqlalchemy.engine import default
-import string, re, sets, weakref
+import string, re, sets, weakref, random
 
 ANSI_FUNCS = sets.ImmutableSet(['CURRENT_DATE', 'CURRENT_TIME', 'CURRENT_TIMESTAMP',
                                 'CURRENT_USER', 'LOCALTIME', 'LOCALTIMESTAMP',
@@ -125,8 +125,8 @@ class ANSICompiler(sql.Compiled):
         # which will be passed to a ResultProxy and used for resultset-level value conversion
         self.typemap = {}
 
-        # a dictionary of select columns mapped to their name or key
-        self.columns = {}
+        # a dictionary of select columns labels mapped to their "generated" label
+        self.column_labels = {}
 
         # True if this compiled represents an INSERT
         self.isinsert = False
@@ -237,16 +237,22 @@ class ANSICompiler(sql.Compiled):
         return ""
 
     def visit_label(self, label):
+        labelname = label.name
+        if len(labelname) >= self.dialect.max_identifier_length():
+            labelname = labelname[0:self.dialect.max_identifier_length() - 6] + "_" + hex(random.randint(0, 65535))[2:]
+        
         if len(self.select_stack):
-            self.typemap.setdefault(label.name.lower(), label.obj.type)
-        self.strings[label] = self.strings[label.obj] + " AS "  + self.preparer.format_label(label)
-
+            self.typemap.setdefault(labelname.lower(), label.obj.type)
+            if isinstance(label.obj, sql._ColumnClause):
+                self.column_labels[label.obj._label] = labelname.lower()
+        self.strings[label] = self.strings[label.obj] + " AS "  + self.preparer.format_label(label, labelname)
+        
     def visit_column(self, column):
         if len(self.select_stack):
             # if we are within a visit to a Select, set up the "typemap"
             # for this column which is used to translate result set values
             self.typemap.setdefault(column.name.lower(), column.type)
-            self.columns.setdefault(column.key, column)
+            self.column_labels.setdefault(column._label, column.name.lower())
         if column.table is None or not column.table.named_with_column():
             self.strings[column] = self.preparer.format_column(column)
         else:
@@ -1015,8 +1021,8 @@ class ANSIIdentifierPreparer(object):
     def format_sequence(self, sequence):
         return self.__generic_obj_format(sequence, sequence.name)
 
-    def format_label(self, label):
-        return self.__generic_obj_format(label, label.name)
+    def format_label(self, label, name=None):
+        return self.__generic_obj_format(label, name or label.name)
 
     def format_alias(self, alias):
         return self.__generic_obj_format(alias, alias.name)