- 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

7 files changed, 246 insertions, 277 deletions

diff --git a/lib/sqlalchemy/dialects/sybase/__init__.py b/lib/sqlalchemy/dialects/sybase/__init__.py
index f8baf339e..573aedde3 100644
--- a/lib/sqlalchemy/dialects/sybase/__init__.py
+++ b/lib/sqlalchemy/dialects/sybase/__init__.py
@@ -1,4 +1,20 @@
-from sqlalchemy.dialects.sybase import base, pyodbc
+from sqlalchemy.dialects.sybase import base, pysybase
+
+
+from base import CHAR, VARCHAR, TIME, NCHAR, NVARCHAR,\
+                            TEXT,DATE,DATETIME, FLOAT, NUMERIC,\
+                            BIGINT,INT, INTEGER, SMALLINT, BINARY,\
+                            VARBINARY,UNITEXT,UNICHAR,UNIVARCHAR,\
+                           IMAGE,BIT,MONEY,SMALLMONEY,TINYINT
 
 # default dialect
-base.dialect = pyodbc.dialect
\ No newline at end of file
+base.dialect = pysybase.dialect
+
+__all__ = (
+     'CHAR', 'VARCHAR', 'TIME', 'NCHAR', 'NVARCHAR',
+    'TEXT','DATE','DATETIME', 'FLOAT', 'NUMERIC',
+    'BIGINT','INT', 'INTEGER', 'SMALLINT', 'BINARY',
+    'VARBINARY','UNITEXT','UNICHAR','UNIVARCHAR',
+   'IMAGE','BIT','MONEY','SMALLMONEY','TINYINT',
+   'dialect'
+)
diff --git a/lib/sqlalchemy/dialects/sybase/base.py b/lib/sqlalchemy/dialects/sybase/base.py
index 886a773d8..2e76a195c 100644
--- a/lib/sqlalchemy/dialects/sybase/base.py
+++ b/lib/sqlalchemy/dialects/sybase/base.py
@@ -5,39 +5,25 @@
 # This module is part of SQLAlchemy and is released under
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
 
-"""Support for the Sybase iAnywhere database.  
+"""Support for Sybase Adaptive Server Enterprise (ASE).
 
-This is not (yet) a full backend for Sybase ASE.
+Note that this dialect is no longer specific to Sybase iAnywhere.
+ASE is the primary support platform.
 
-This dialect is *not* ported to SQLAlchemy 0.6.
-
-This dialect is *not* tested on SQLAlchemy 0.6.
-
-
-Known issues / TODO:
-
- * Uses the mx.ODBC driver from egenix (version 2.1.0)
- * The current version of sqlalchemy.databases.sybase only supports
-   mx.ODBC.Windows (other platforms such as mx.ODBC.unixODBC still need
-   some development)
- * Support for pyodbc has been built in but is not yet complete (needs
-   further development)
- * Results of running tests/alltests.py:
-     Ran 934 tests in 287.032s
-     FAILED (failures=3, errors=1)
- * Tested on 'Adaptive Server Anywhere 9' (version 9.0.1.1751)
 """
 
-import datetime, operator
-
-from sqlalchemy import util, sql, schema, exc
+import operator
 from sqlalchemy.sql import compiler, expression
-from sqlalchemy.engine import default, base
+from sqlalchemy.engine import default, base, reflection
 from sqlalchemy import types as sqltypes
 from sqlalchemy.sql import operators as sql_operators
-from sqlalchemy import MetaData, Table, Column
-from sqlalchemy import String, Integer, SMALLINT, CHAR, ForeignKey
-from sqlalchemy.dialects.sybase.schema import *
+from sqlalchemy import schema as sa_schema
+from sqlalchemy import util, sql, exc
+
+from sqlalchemy.types import CHAR, VARCHAR, TIME, NCHAR, NVARCHAR,\
+                            TEXT,DATE,DATETIME, FLOAT, NUMERIC,\
+                            BIGINT,INT, INTEGER, SMALLINT, BINARY,\
+                            VARBINARY
 
 RESERVED_WORDS = set([
     "add", "all", "alter", "and",
@@ -99,23 +85,33 @@ RESERVED_WORDS = set([
     ])
 
 
-class SybaseImage(sqltypes.LargeBinary):
-    __visit_name__ = 'IMAGE'
+class UNICHAR(sqltypes.Unicode):
+    __visit_name__ = 'UNICHAR'
+
+class UNIVARCHAR(sqltypes.Unicode):
+    __visit_name__ = 'UNIVARCHAR'
+
+class UNITEXT(sqltypes.UnicodeText):
+    __visit_name__ = 'UNITEXT'
 
-class SybaseBit(sqltypes.TypeEngine):
+class TINYINT(sqltypes.Integer):
+    __visit_name__ = 'TINYINT'
+
+class BIT(sqltypes.TypeEngine):
     __visit_name__ = 'BIT'
     
-class SybaseMoney(sqltypes.TypeEngine):
+class MONEY(sqltypes.TypeEngine):
     __visit_name__ = "MONEY"
 
-class SybaseSmallMoney(SybaseMoney):
+class SMALLMONEY(sqltypes.TypeEngine):
     __visit_name__ = "SMALLMONEY"
 
-class SybaseUniqueIdentifier(sqltypes.TypeEngine):
+class UNIQUEIDENTIFIER(sqltypes.TypeEngine):
     __visit_name__ = "UNIQUEIDENTIFIER"
-    
-class SybaseBoolean(sqltypes.Boolean):
-    pass
+  
+class IMAGE(sqltypes.LargeBinary):
+    __visit_name__ = 'IMAGE'
+ 
 
 class SybaseTypeCompiler(compiler.GenericTypeCompiler):
     def visit_large_binary(self, type_):
@@ -123,6 +119,15 @@ class SybaseTypeCompiler(compiler.GenericTypeCompiler):
     
     def visit_boolean(self, type_):
         return self.visit_BIT(type_)
+
+    def visit_UNICHAR(self, type_):
+        return "UNICHAR(%d)" % type_.length
+
+    def visit_UNITEXT(self, type_):
+        return "UNITEXT"
+
+    def visit_TINYINT(self, type_):
+        return "TINYINT"
         
     def visit_IMAGE(self, type_):
         return "IMAGE"
@@ -140,56 +145,41 @@ class SybaseTypeCompiler(compiler.GenericTypeCompiler):
         return "UNIQUEIDENTIFIER"
         
 colspecs = {
-    sqltypes.LargeBinary : SybaseImage,
-    sqltypes.Boolean : SybaseBoolean,
 }
 
 ischema_names = {
-    'integer' : sqltypes.INTEGER,
-    'unsigned int' : sqltypes.Integer,
-    'unsigned smallint' : sqltypes.SmallInteger,
-    'unsigned bigint' : sqltypes.BigInteger,
-    'bigint': sqltypes.BIGINT,
-    'smallint' : sqltypes.SMALLINT,
-    'tinyint' : sqltypes.SmallInteger,
-    'varchar' : sqltypes.VARCHAR,
-    'long varchar' : sqltypes.Text,
-    'char' : sqltypes.CHAR,
-    'decimal' : sqltypes.DECIMAL,
-    'numeric' : sqltypes.NUMERIC,
-    'float' : sqltypes.FLOAT,
-    'double' : sqltypes.Numeric,
-    'binary' : sqltypes.LargeBinary,
-    'long binary' : sqltypes.LargeBinary,
-    'varbinary' : sqltypes.LargeBinary,
-    'bit': SybaseBit,
-    'image' : SybaseImage,
-    'timestamp': sqltypes.TIMESTAMP,
-    'money': SybaseMoney,
-    'smallmoney': SybaseSmallMoney,
-    'uniqueidentifier': SybaseUniqueIdentifier,
+    'integer' : INTEGER,
+    'unsigned int' : INTEGER, # TODO: unsigned flags
+    'unsigned smallint' : SMALLINT, # TODO: unsigned flags
+    'unsigned bigint' : BIGINT, # TODO: unsigned flags
+    'bigint': BIGINT,
+    'smallint' : SMALLINT,
+    'tinyint' : TINYINT,
+    'varchar' : VARCHAR,
+    'long varchar' : TEXT, # TODO
+    'char' : CHAR,
+    'decimal' : DECIMAL,
+    'numeric' : NUMERIC,
+    'float' : FLOAT,
+    'double' : NUMERIC, # TODO
+    'binary' : BINARY,
+    'varbinary' : VARBINARY,
+    'bit': BIT,
+    'image' : IMAGE,
+    'timestamp': TIMESTAMP,
+    'money': MONEY,
+    'smallmoney': MONEY,
+    'uniqueidentifier': UNIQUEIDENTIFIER,
 
 }
 
 
 class SybaseExecutionContext(default.DefaultExecutionContext):
-
     def post_exec(self):
-        if self.compiled.isinsert:
-            table = self.compiled.statement.table
-            # get the inserted values of the primary key
-
-            # get any sequence IDs first (using @@identity)
+        if self.isinsert and not self.executemany:
             self.cursor.execute("SELECT @@identity AS lastrowid")
-            row = self.cursor.fetchone()
-            lastrowid = int(row[0])
-            if lastrowid > 0:
-                # an IDENTITY was inserted, fetch it
-                # FIXME: always insert in front ? This only works if the IDENTITY is the first column, no ?!
-                if not hasattr(self, '_last_inserted_ids') or self._last_inserted_ids is None:
-                    self._last_inserted_ids = [lastrowid]
-                else:
-                    self._last_inserted_ids = [lastrowid] + self._last_inserted_ids[1:]
+            row = self.cursor.fetchall()[0]
+            self._lastrowid = int(row[0])
 
 
 class SybaseSQLCompiler(compiler.SQLCompiler):
@@ -204,12 +194,6 @@ class SybaseSQLCompiler(compiler.SQLCompiler):
     def visit_mod(self, binary, **kw):
         return "MOD(%s, %s)" % (self.process(binary.left), self.process(binary.right))
 
-    def bindparam_string(self, name):
-        res = super(SybaseSQLCompiler, self).bindparam_string(name)
-        if name.lower().startswith('literal'):
-            res = 'STRING(%s)' % res
-        return res
-
     def get_select_precolumns(self, select):
         s = select._distinct and "DISTINCT " or ""
         if select._limit:
@@ -230,32 +214,22 @@ class SybaseSQLCompiler(compiler.SQLCompiler):
         # Limit in sybase is after the select keyword
         return ""
 
-    def visit_binary(self, binary):
+    def dont_visit_binary(self, binary):
         """Move bind parameters to the right-hand side of an operator, where possible."""
         if isinstance(binary.left, expression._BindParamClause) and binary.operator == operator.eq:
             return self.process(expression._BinaryExpression(binary.right, binary.left, binary.operator))
         else:
             return super(SybaseSQLCompiler, self).visit_binary(binary)
 
-    def label_select_column(self, select, column, asfrom):
+    def dont_label_select_column(self, select, column, asfrom):
         if isinstance(column, expression.Function):
             return column.label(None)
         else:
             return super(SybaseSQLCompiler, self).label_select_column(select, column, asfrom)
 
-    function_rewrites =  {'current_date': 'getdate',
-                         }
-    def visit_function(self, func):
-        func.name = self.function_rewrites.get(func.name, func.name)
-        res = super(SybaseSQLCompiler, self).visit_function(func)
-        if func.name.lower() == 'getdate':
-            # apply CAST operator
-            # FIXME: what about _pyodbc ?
-            cast = expression._Cast(func, SybaseDate_mxodbc)
-            # infinite recursion
-            # res = self.visit_cast(cast)
-            res = "CAST(%s AS %s)" % (res, self.process(cast.typeclause))
-        return res
+#    def visit_getdate_func(self, fn, **kw):
+         # TODO: need to cast? something ?
+#        pass
 
     def visit_extract(self, extract):
         field = self.extract_map.get(extract.field, extract.field)
@@ -277,27 +251,38 @@ class SybaseSQLCompiler(compiler.SQLCompiler):
 
 class SybaseDDLCompiler(compiler.DDLCompiler):
     def get_column_specification(self, column, **kwargs):
+        colspec = self.preparer.format_column(column) + " " + \
+                                   self.dialect.type_compiler.process(column.type)
 
-        colspec = self.preparer.format_column(column)
+        if column.table is None:
+            raise exc.InvalidRequestError("The Sybase dialect requires Table-bound "\
+                                                   "columns in order to generate DDL")
+        seq_col = column.table._autoincrement_column
 
-        if (not getattr(column.table, 'has_sequence', False)) and column.primary_key and \
-                column.autoincrement and isinstance(column.type, sqltypes.Integer):
-            if column.default is None or (isinstance(column.default, schema.Sequence) and column.default.optional):
-                column.sequence = schema.Sequence(column.name + '_seq')
+            
 
-        if hasattr(column, 'sequence'):
-            column.table.has_sequence = column
-            #colspec += " numeric(30,0) IDENTITY"
-            colspec += " Integer IDENTITY"
+        # install a IDENTITY Sequence if we have an implicit IDENTITY column
+        if seq_col is column:
+            sequence = isinstance(column.default, sa_schema.Sequence) and column.default
+            if sequence:
+                start, increment = sequence.start or 1, sequence.increment or 1
+            else:
+                start, increment = 1, 1
+            if (start, increment) == (1, 1):
+                colspec += " IDENTITY"
+            else:
+                # TODO: need correct syntax for this
+                colspec += " IDENTITY(%s,%s)" % (start, increment)
         else:
-            colspec += " " + self.dialect.type_compiler.process(column.type)
-
-        if not column.nullable:
-            colspec += " NOT NULL"
+            if column.nullable is not None:
+                if not column.nullable or column.primary_key:
+                    colspec += " NOT NULL"
+                else:
+                    colspec += " NULL"
 
-        default = self.get_column_default_string(column)
-        if default is not None:
-            colspec += " DEFAULT " + default
+            default = self.get_column_default_string(column)
+            if default is not None:
+                colspec += " DEFAULT " + default
 
         return colspec
 
@@ -324,120 +309,47 @@ class SybaseDialect(default.DefaultDialect):
     ddl_compiler = SybaseDDLCompiler
     preparer = SybaseIdentifierPreparer
 
-    ported_sqla_06 = False
-
-    schema_name = "dba"
-
-    def __init__(self, **params):
-        super(SybaseDialect, self).__init__(**params)
-        self.text_as_varchar = False
-
-    def last_inserted_ids(self):
-        return self.context.last_inserted_ids
-
     def _get_default_schema_name(self, connection):
-        # TODO
-        return self.schema_name
+        return connection.scalar(
+                     text("SELECT user_name() as user_name", typemap={'user_name':Unicode})
+             )
+
+    @reflection.cache
+    def get_table_names(self, connection, schema=None, **kw):
+        if schema is None:
+            schema = self.default_schema_name
+        return self.table_names(connection, schema)
 
     def table_names(self, connection, schema):
-        """Ignore the schema and the charset for now."""
-        s = sql.select([tables.c.table_name],
-                       sql.not_(tables.c.table_name.like("SYS%")) and
-                       tables.c.creator >= 100
-                       )
-        rp = connection.execute(s)
-        return [row[0] for row in rp.fetchall()]
+
+        result = connection.execute(
+                    text("select sysobjects.name from sysobjects, sysusers "
+                         "where sysobjects.uid=sysusers.uid and "
+                         "sysusers.name=:schemaname and "
+                         "sysobjects.type='U'",
+                         bindparams=[
+                                  bindparam('schemaname', schema)
+                                  ])
+         )
+        return [r[0] for r in result]
 
     def has_table(self, connection, tablename, schema=None):
-        # FIXME: ignore schemas for sybase
-        s = sql.select([tables.c.table_name], tables.c.table_name == tablename)
-        return connection.execute(s).first() is not None
+        if schema is None:
+            schema = self.default_schema_name
+
+        result = connection.execute(
+                    text("select sysobjects.name from sysobjects, sysusers "
+                         "where sysobjects.uid=sysusers.uid and "
+                         "sysobjects.name=:tablename and "
+                         "sysusers.name=:schemaname and "
+                         "sysobjects.type='U'",
+                         bindparams=[
+                                  bindparam('tablename', tablename),
+                                  bindparam('schemaname', schema)
+                                  ])
+                 )
+        return result.scalar() is not None
 
     def reflecttable(self, connection, table, include_columns):
-        # Get base columns
-        if table.schema is not None:
-            current_schema = table.schema
-        else:
-            current_schema = self.default_schema_name
-
-        s = sql.select([columns, domains], tables.c.table_name==table.name, from_obj=[columns.join(tables).join(domains)], order_by=[columns.c.column_id])
-
-        c = connection.execute(s)
-        found_table = False
-        # makes sure we append the columns in the correct order
-        while True:
-            row = c.fetchone()
-            if row is None:
-                break
-            found_table = True
-            (name, type, nullable, charlen, numericprec, numericscale, default, primary_key, max_identity, table_id, column_id) = (
-                row[columns.c.column_name],
-                row[domains.c.domain_name],
-                row[columns.c.nulls] == 'Y',
-                row[columns.c.width],
-                row[domains.c.precision],
-                row[columns.c.scale],
-                row[columns.c.default],
-                row[columns.c.pkey] == 'Y',
-                row[columns.c.max_identity],
-                row[tables.c.table_id],
-                row[columns.c.column_id],
-            )
-            if include_columns and name not in include_columns:
-                continue
-
-            # FIXME: else problems with SybaseBinary(size)
-            if numericscale == 0:
-                numericscale = None
-
-            args = []
-            for a in (charlen, numericprec, numericscale):
-                if a is not None:
-                    args.append(a)
-            coltype = self.ischema_names.get(type, None)
-            if coltype == SybaseString and charlen == -1:
-                coltype = SybaseText()
-            else:
-                if coltype is None:
-                    util.warn("Did not recognize type '%s' of column '%s'" %
-                              (type, name))
-                    coltype = sqltypes.NULLTYPE
-                coltype = coltype(*args)
-            colargs = []
-            if default is not None:
-                colargs.append(schema.DefaultClause(sql.text(default)))
-
-            # any sequences ?
-            col = schema.Column(name, coltype, nullable=nullable, primary_key=primary_key, *colargs)
-            if int(max_identity) > 0:
-                col.sequence = schema.Sequence(name + '_identity')
-                col.sequence.start = int(max_identity)
-                col.sequence.increment = 1
-
-            # append the column
-            table.append_column(col)
-
-        # any foreign key constraint for this table ?
-        # note: no multi-column foreign keys are considered
-        s = "select st1.table_name, sc1.column_name, st2.table_name, sc2.column_name from systable as st1 join sysfkcol on st1.table_id=sysfkcol.foreign_table_id join sysforeignkey join systable as st2 on sysforeignkey.primary_table_id = st2.table_id join syscolumn as sc1 on sysfkcol.foreign_column_id=sc1.column_id and sc1.table_id=st1.table_id join syscolumn as sc2 on sysfkcol.primary_column_id=sc2.column_id and sc2.table_id=st2.table_id where st1.table_name='%(table_name)s';" % { 'table_name' : table.name }
-        c = connection.execute(s)
-        foreignKeys = {}
-        while True:
-            row = c.fetchone()
-            if row is None:
-                break
-            (foreign_table, foreign_column, primary_table, primary_column) = (
-                row[0], row[1], row[2], row[3],
-            )
-            if not primary_table in foreignKeys.keys():
-                foreignKeys[primary_table] = [['%s' % (foreign_column)], ['%s.%s'%(primary_table, primary_column)]]
-            else:
-                foreignKeys[primary_table][0].append('%s'%(foreign_column))
-                foreignKeys[primary_table][1].append('%s.%s'%(primary_table, primary_column))
-        for primary_table in foreignKeys.iterkeys():
-            #table.append_constraint(schema.ForeignKeyConstraint(['%s.%s'%(foreign_table, foreign_column)], ['%s.%s'%(primary_table,primary_column)]))
-            table.append_constraint(schema.ForeignKeyConstraint(foreignKeys[primary_table][0], foreignKeys[primary_table][1], link_to_name=True))
-
-        if not found_table:
-            raise exc.NoSuchTableError(table.name)
+        raise NotImplementedError()
 
diff --git a/lib/sqlalchemy/dialects/sybase/mxodbc.py b/lib/sqlalchemy/dialects/sybase/mxodbc.py
index 86a23d5bc..274ffd99a 100644
--- a/lib/sqlalchemy/dialects/sybase/mxodbc.py
+++ b/lib/sqlalchemy/dialects/sybase/mxodbc.py
@@ -1,3 +1,10 @@
+"""
+Support for Sybase via mxodbc.
+
+This dialect is a stub only and is likely non functional at this time.
+
+
+"""
 from sqlalchemy.dialects.sybase.base import SybaseDialect, SybaseExecutionContext
 from sqlalchemy.connectors.mxodbc import MxODBCConnector
 
@@ -7,4 +14,4 @@ class SybaseExecutionContext_mxodbc(SybaseExecutionContext):
 class Sybase_mxodbc(MxODBCConnector, SybaseDialect):
     execution_ctx_cls = SybaseExecutionContext_mxodbc
 
-dialect = Sybase_mxodbc
\ No newline at end of file
+dialect = Sybase_mxodbc
diff --git a/lib/sqlalchemy/dialects/sybase/pyodbc.py b/lib/sqlalchemy/dialects/sybase/pyodbc.py
index 61c6f3292..12d7a21db 100644
--- a/lib/sqlalchemy/dialects/sybase/pyodbc.py
+++ b/lib/sqlalchemy/dialects/sybase/pyodbc.py
@@ -1,3 +1,11 @@
+"""
+Support for Sybase via pyodbc.
+
+This dialect is a stub only and is likely non functional at this time.
+
+
+"""
+
 from sqlalchemy.dialects.sybase.base import SybaseDialect, SybaseExecutionContext
 from sqlalchemy.connectors.pyodbc import PyODBCConnector
 
@@ -8,4 +16,4 @@ class SybaseExecutionContext_pyodbc(SybaseExecutionContext):
 class Sybase_pyodbc(PyODBCConnector, SybaseDialect):
     execution_ctx_cls = SybaseExecutionContext_pyodbc
 
-dialect = Sybase_pyodbc
\ No newline at end of file
+dialect = Sybase_pyodbc
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
diff --git a/lib/sqlalchemy/dialects/sybase/schema.py b/lib/sqlalchemy/dialects/sybase/schema.py
deleted file mode 100644
index 15ac6b27b..000000000
--- a/lib/sqlalchemy/dialects/sybase/schema.py
+++ /dev/null
@@ -1,51 +0,0 @@
-from sqlalchemy import *
-
-ischema = MetaData()
-
-tables = Table("SYSTABLE", ischema,
-    Column("table_id", Integer, primary_key=True),
-    Column("file_id", SMALLINT),
-    Column("table_name", CHAR(128)),
-    Column("table_type", CHAR(10)),
-    Column("creator", Integer),
-    #schema="information_schema"
-    )
-
-domains = Table("SYSDOMAIN", ischema,
-    Column("domain_id", Integer, primary_key=True),
-    Column("domain_name", CHAR(128)),
-    Column("type_id", SMALLINT),
-    Column("precision", SMALLINT, quote=True),
-    #schema="information_schema"
-    )
-
-columns = Table("SYSCOLUMN", ischema,
-    Column("column_id", Integer, primary_key=True),
-    Column("table_id", Integer, ForeignKey(tables.c.table_id)),
-    Column("pkey", CHAR(1)),
-    Column("column_name", CHAR(128)),
-    Column("nulls", CHAR(1)),
-    Column("width", SMALLINT),
-    Column("domain_id", SMALLINT, ForeignKey(domains.c.domain_id)),
-    # FIXME: should be mx.BIGINT
-    Column("max_identity", Integer),
-    # FIXME: should be mx.ODBC.Windows.LONGVARCHAR
-    Column("default", String),
-    Column("scale", Integer),
-    #schema="information_schema"
-    )
-
-foreignkeys = Table("SYSFOREIGNKEY", ischema,
-    Column("foreign_table_id", Integer, ForeignKey(tables.c.table_id), primary_key=True),
-    Column("foreign_key_id", SMALLINT, primary_key=True),
-    Column("primary_table_id", Integer, ForeignKey(tables.c.table_id)),
-    #schema="information_schema"
-    )
-fkcols = Table("SYSFKCOL", ischema,
-    Column("foreign_table_id", Integer, ForeignKey(columns.c.table_id), primary_key=True),
-    Column("foreign_key_id", SMALLINT, ForeignKey(foreignkeys.c.foreign_key_id), primary_key=True),
-    Column("foreign_column_id", Integer, ForeignKey(columns.c.column_id), primary_key=True),
-    Column("primary_column_id", Integer),
-    #schema="information_schema"
-    )
-
diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 8222c93cd..7df858a64 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -135,7 +135,9 @@ class DefaultDialect(base.Dialect):
             self.default_schema_name = None
 
         self.returns_unicode_strings = self._check_unicode_returns(connection)
-    
+   
+        self.do_rollback(connection.connection)
+ 
     def _check_unicode_returns(self, connection):
         # Py2K
         if self.supports_unicode_statements:
@@ -257,6 +259,7 @@ class DefaultExecutionContext(base.ExecutionContext):
     isinsert = False
     isupdate = False
     isdelete = False
+    isddl = False
     executemany = False
     result_map = None
     compiled = None
@@ -276,6 +279,7 @@ class DefaultExecutionContext(base.ExecutionContext):
         
         if compiled_ddl is not None:
             self.compiled = compiled = compiled_ddl
+            self.isddl = True
 
             if compiled.statement._execution_options:
                 self.execution_options = compiled.statement._execution_options