morro

sqlalchemy/dialects/mssql/pymssql.py

@@ -0,0 +1,101 @@
+"""
+Support for the pymssql dialect.
+
+This dialect supports pymssql 1.0 and greater.
+
+pymssql is available at:
+
+    http://pymssql.sourceforge.net/
+    
+Connecting
+^^^^^^^^^^
+    
+Sample connect string::
+
+    mssql+pymssql://<username>:<password>@<freetds_name>
+
+Adding "?charset=utf8" or similar will cause pymssql to return
+strings as Python unicode objects.   This can potentially improve 
+performance in some scenarios as decoding of strings is 
+handled natively.
+
+Limitations
+^^^^^^^^^^^
+
+pymssql inherits a lot of limitations from FreeTDS, including:
+
+* no support for multibyte schema identifiers
+* poor support for large decimals
+* poor support for binary fields
+* poor support for VARCHAR/CHAR fields over 255 characters
+
+Please consult the pymssql documentation for further information.
+
+"""
+from sqlalchemy.dialects.mssql.base import MSDialect
+from sqlalchemy import types as sqltypes, util, processors
+import re
+import decimal
+
+class _MSNumeric_pymssql(sqltypes.Numeric):
+    def result_processor(self, dialect, type_):
+        if not self.asdecimal:
+            return processors.to_float
+        else:
+            return sqltypes.Numeric.result_processor(self, dialect, type_)
+
+class MSDialect_pymssql(MSDialect):
+    supports_sane_rowcount = False
+    max_identifier_length = 30
+    driver = 'pymssql'
+    
+    colspecs = util.update_copy(
+        MSDialect.colspecs,
+        {
+            sqltypes.Numeric:_MSNumeric_pymssql,
+            sqltypes.Float:sqltypes.Float,
+        }
+    )
+    @classmethod
+    def dbapi(cls):
+        module = __import__('pymssql')
+        # pymmsql doesn't have a Binary method.  we use string
+        # TODO: monkeypatching here is less than ideal
+        module.Binary = str
+        
+        client_ver = tuple(int(x) for x in module.__version__.split("."))
+        if client_ver < (1, ):
+            util.warn("The pymssql dialect expects at least "
+                            "the 1.0 series of the pymssql DBAPI.")
+        return module
+
+    def __init__(self, **params):
+        super(MSDialect_pymssql, self).__init__(**params)
+        self.use_scope_identity = True
+
+    def _get_server_version_info(self, connection):
+        vers = connection.scalar("select @@version")
+        m = re.match(r"Microsoft SQL Server.*? - (\d+).(\d+).(\d+).(\d+)", vers)
+        if m:
+            return tuple(int(x) for x in m.group(1, 2, 3, 4))
+        else:
+            return None
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username='user')
+        opts.update(url.query)
+        opts.pop('port', None)
+        return [[], opts]
+
+    def is_disconnect(self, e):
+        for msg in (
+            "Error 10054",
+            "Not connected to any MS SQL server",
+            "Connection is closed"
+        ):
+            if msg in str(e):
+                return True
+        else:
+            return False
+
+dialect = MSDialect_pymssql