- initial working version of sybase, with modifications to the transactional

model to accomodate Sybase's default mode of "no ddl in transactions".
- identity insert not working yet.  it seems the default here might be the
opposite of that of MSSQL.
- reflection will be a full rewrite
- default DBAPI is python-sybase, well documented and nicely DBAPI compliant
except for the bind parameter situation, where we have a straightforward workaround
- full Sybase docs at: http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.ase_15.0/title.htm

1 files changed, 73 insertions, 0 deletions

diff --git a/lib/sqlalchemy/dialects/sybase/pysybase.py b/lib/sqlalchemy/dialects/sybase/pysybase.py
new file mode 100644
index 000000000..e58c6d986
--- /dev/null
+++ b/lib/sqlalchemy/dialects/sybase/pysybase.py
@@ -0,0 +1,73 @@
+# pysybase.py
+# Copyright (C) 2010 Michael Bayer mike_mp@zzzcomputing.com
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: http://www.opensource.org/licenses/mit-license.php
+
+"""
+Support for Sybase via the python-sybase driver.
+
+http://python-sybase.sourceforge.net/
+
+Connect strings are of the form::
+
+    sybase+pysybase://<username>:<password>@<dsn>/[database name]
+
+"""
+
+from sqlalchemy.dialects.sybase.base import SybaseDialect, \
+                                        SybaseExecutionContext, SybaseSQLCompiler
+
+
+class SybaseExecutionContext_pysybase(SybaseExecutionContext):
+    def pre_exec(self):
+        for param in self.parameters:
+            for key in list(param):
+                param["@" + key] = param[key]
+                del param[key]
+
+        if self.isddl:
+            # TODO: to enhance this, we can detect "ddl in tran" on the
+            # database settings.  this error message should be improved to 
+            # include a note about that.
+            if not self.should_autocommit:
+                raise exc.InvalidRequestError("The Sybase dialect only supports "
+                                            "DDL in 'autocommit' mode at this time.")
+            # call commit() on the Sybase connection directly,
+            # to avoid any side effects of calling a Connection 
+            # transactional method inside of pre_exec()
+            self.root_connection.engine.logger.info("COMMIT (Assuming no Sybase 'ddl in tran')")
+            self.root_connection.connection.commit()
+
+class SybaseSQLCompiler_pysybase(SybaseSQLCompiler):
+    def bindparam_string(self, name):
+        return "@" + name
+   
+class SybaseDialect_pysybase(SybaseDialect):
+    driver = 'pysybase'
+    execution_ctx_cls = SybaseExecutionContext_pysybase
+    statement_compiler = SybaseSQLCompiler_pysybase
+
+    @classmethod
+    def dbapi(cls):
+        import Sybase
+        return Sybase
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username='user', password='passwd')
+
+        return ([opts.pop('host')], opts)
+
+    def _get_server_version_info(self, connection):
+       return connection.scalar("select @@version_number")
+
+    def is_disconnect(self, e):
+        if isinstance(e, (self.dbapi.OperationalError, self.dbapi.ProgrammingError)):
+            msg = str(e)
+            return ('Unable to complete network request to host' in msg or
+                    'Invalid connection state' in msg or
+                    'Invalid cursor state' in msg)
+        else:
+            return False
+
+dialect = SybaseDialect_pysybase