- Dialects can now generate label names of adjustable length.

Pass in the argument "label_length=<value>" to create_engine()
to adjust how many characters max will be present in dynamically
generated column labels, i.e. "somecolumn AS somelabel".  Any
value less than 6 will result in a label of minimal size,
consiting of an underscore and a numeric counter.
The compiler uses the value of dialect.max_identifier_length
as a default. [ticket:1211]
- removed ANON_NAME regular expression, using string patterns now
- _generated_label() unicode subclass is used to indicate generated names
which are subject to truncation

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index f99cac465..ec15313e4 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -40,7 +40,7 @@ class DefaultDialect(base.Dialect):
     supports_default_values = False 
     supports_empty_insert = True
 
-    def __init__(self, convert_unicode=False, assert_unicode=False, encoding='utf-8', paramstyle=None, dbapi=None, **kwargs):
+    def __init__(self, convert_unicode=False, assert_unicode=False, encoding='utf-8', paramstyle=None, dbapi=None, label_length=None, **kwargs):
         self.convert_unicode = convert_unicode
         self.assert_unicode = assert_unicode
         self.encoding = encoding
@@ -55,6 +55,9 @@ class DefaultDialect(base.Dialect):
             self.paramstyle = self.default_paramstyle
         self.positional = self.paramstyle in ('qmark', 'format', 'numeric')
         self.identifier_preparer = self.preparer(self)
+        if label_length and label_length > self.max_identifier_length:
+            raise exc.ArgumentError("Label length of %d is greater than this dialect's maximum identifier length of %d" % (label_length, self.max_identifier_length))
+        self.label_length = label_length
 
     def create_execution_context(self, connection, **kwargs):
         return DefaultExecutionContext(self, connection, **kwargs)