The problem with the connection being returned to the pool was due to
executing the SET IDENTITY_INSERT statement on the *cursor* rather
than the *connection*. The documentation states that the connection
will be returned to the pool when a statement is executed on it that
doesn't return any results (such as the SET statement). using
self.connection.execute solved that problem.
There was a difficult to diagnose problem with python-sybase in that
sometimes the keys of the parameter dict were in unicode which caused
the buf.name = name assignment to throw a TypeError. Coercing the
param keys via str() solved that problem.
In Sybase, a column declaration without NULL/NOT NULL defaults to NOT
NULL so a bunch of the tests need to be updated.
The schema introspection stuff seems to work OK albeit with some low-
level querying of the system tables. I started off with a higher-level
implementation but abandoned it due to all kinds of (possibly
spurious) problems. There are still some problems with the test tear-
downs as tables are not being dropped in the correct order.
All in all, the driver is now in a state that can be called
'buggy' (as opposed to being completely dysfunctional)
pjjH
On Feb 27, 4:29 pm, "phrrn...@googlemail.com"
<phrrn...@googlemail.com> wrote:
> Yes, it is based off the mssql code but I made some modifications to
> it to take care of situations like, for example, where there is an
> identity column but it is not the primary key (and hence not a
> 'sequence'). This means a read off the catalog to find the identity
> column (I believe that only one identity column is permitted per
> table). I was wondering if some 'bad thing' happens if you execute a
> select on the cursor and retrieve results when you are in the
> pre_exec.
>
> I don't know what you are referring to when you say 'throw a pdb' .. I
> hope it has something to do with the debugger!
>
> As for being in deep, I am afraid we are only starting: Sybase has
> enough 'special' stuff to keep us busy for a long time e.g. cross-
> database referential integrity constraints. database-specific default
> schemas (e.g. login foo may have schema 'dbo' in database apple but
> schema 'guest' in database pear and schema 'prod' in database banana).
> Then what does one do about remote objects mapped in via CIS (e.g.
> REMOTE.production.dbo.very_important_table) (actually this is a
> problem with SQL Server also)
>
> pjjH
>
> On Feb 27, 4:05 pm, "Michael Bayer" <mike...@zzzcomputing.com> wrote:
>
> > phrrn...@googlemail.com wrote:
>
> > > I want to automatically set IDENTITY_INSERT for a table if the
> > > identity column is explicitly listed. Likewise, after execution of an
> > > insert on a table with an identity column we want to retrieve the
> > > identity value.
>
> > > Any idea why the following code would cause the connection to be
> > > checked in between the pre_exec() and the actual execution of the
> > > statement? I have enabled high levels of debugging on the python-
> > > sybase driver and can see that a new connection is made *after* the
> > > 'SET IDENTITY_INSERT foo ON' and the actual command runs on that new
> > > connection (and, of course, fails as IDENTITY_INSERT is not enabled on
> > > that table for the new connection).
>
> > Assuming you took that code from the MSSQL dialect, it should be fine.
> > that looks like an older version of it, though...in 0.6 take a look in
> > mssql/base.py for the latest version of the IDENTITY_INSERT dance.
>
> > but no there's nothing in there in any case that would cause a second
> > connection to be checked out. throw a pdb into the Connection constructor,
> > or perhaps in pool.connect(), to track where that's coming from.
>
> > sorry you're in deep .... :)
>
> > > pjjH
>
> > > class SybaseSQLExecutionContext(default.DefaultExecutionContext):
> > > def _table_identity_column(self, t):
> > > """Return the name of the this table's identity column"""
> > > # negative caching
> > > if not hasattr(t, '_identity_column'):
> > > t._identity_column = None
> > > s = r"""SELECT cols.name FROM syscolumns as cols JOIN
> > > sysobjects as o ON (cols.id = o.id) WHERE o.name ='%s' and cols.status
> > > & 0x80 = 0x80""" % (t.name)
> > > self.cursor.execute(s)
> > > r = self.cursor.fetchone()
> > > if r:
> > > t._identity_column = r[0]
> > > return t._identity_column
>
> > > def pre_exec(self):
> > > self.HAS_IDENTITY = False
> > > self.IDENTITY_INSERT = False
> > > # What about UPDATE statements? Is this even possible in
> > > Sybase?
> > > if self.compiled.isinsert:
> > > if self._table_identity_column
> > > (self.compiled.statement.table):
> > > self.HAS_IDENTITY = True
> > > identity_column = self._table_identity_column
> > > (self.compiled.statement.table)
> > > if identity_column in self.compiled_parameters[0].keys
> > > ():
> > > self.IDENTITY_INSERT = True
> > > self.cursor.execute("SET IDENTITY_INSERT %s ON" %
>
> > > self.dialect.identifier_preparer.format_table
> > > (self.compiled.statement.table))
>
> > > def post_exec(self):
> > > if self.HAS_IDENTITY:
> > > self.cursor.execute("SELECT @@identity AS lastrowid")
> > > lastrowid = self.cursor.fetchone()[0]
> > > if lastrowid > 0:
> > > 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:]
>
> > > if self.IDENTITY_INSERT:
> > > self.cursor.execute("SET IDENTITY_INSERT %s OFF" %
> > > self.dialect.identifier_preparer.format_table
> > > (self.compiled.statement.table))
>
> > > On Feb 27, 2:02 pm, "phrrn...@googlemail.com"
> > > <phrrn...@googlemail.com> wrote:
> > >> OK. I will do the development work against the 0.6 tree. I may end up
> > >> backporting it to 0.5 as I want to get in into use at work as soon as
> > >> is reasonable (which may be prior to the 0.6 release)
>
> > >> pjjH
>
> > >> On Feb 27, 11:29 am, "Michael Bayer" <mike...@zzzcomputing.com> wrote:
>
> > >> > phrrn...@googlemail.com wrote:
>
> > >> > > How does one deal with driver-specific unit tests? I am running in
> > >> > > difficulties in testing the pyodbc and python-sybase drivers for the
> > >> > > sybase dialect. For example, test_raw_qmark works with the pyodbc
> > >> > > driver (as it supports that style) but not with the python-sybase
> > >> > > driver. Is there some decorator available that can help with
> > >> skipping
> > >> > > certain tests for a given DBABI driver. Any suggestions on how to
> > >> > > handle this?
>
> > >> > most tests make usage of decorators like @testing.fails_on to mark
> > >> various
> > >> > databases as unsupported. That test in particular is very specific to
> > >> > certain DBAPIs, i.e. those that support "qmark" bind parameters. For
> > >> the
> > >> > "lesser" databases like MSSQL and Firebird, i.e. those which have lots
> > >> of
> > >> > missing features, hundreds of decorators are configured to exclude
> > >> them.
> > >> > You would have a similar task in the case of sybase.
>
> > >> > But to be specific regarding pyodbc vs. python-sybase, that is exactly
> > >> > what's addressed in SQLA 0.6. If you look there you'll see the
> > >> decorators
> > >> > can differentiate among multiple DBAPIs for the same dialect, i.e.
> > >> > sybase+pyodbc vs. sybase+python-sybase in this case. There is also a
> > >> > coherent non-guesswork system of using specific drivers.
>
> > >> > just so you know we'd really like SQLA 0.6 to be released soon after
> > >> > pycon. There's not that much work to be done on it for a release.
> > >> The
> > >> > only reason its a "major" number is because the API for dialects does
> > >> > change considerably.
>
> > >> > > pjjH
>
> > >> > > On Feb 26, 5:31 pm, Michael Bayer <mike...@zzzcomputing.com> wrote:
> > >> > >> we have ticket 785 for this:
>
> > >> > >>http://www.sqlalchemy.org/trac/ticket/785
>
> > >> > >> On Feb 26, 2009, at 4:45 PM, phrrn...@googlemail.com wrote:
>
> > >> > >> > Thanks Michael. I have a sybase.py passing *some* unit tests with
> > >> both
> > >> > >> > pyodbc and the Sybase driver, both running on Solaris 10 x86
> > >> against
> > >> > >> > ASE 15. This is a hack that seems to work for the Sybase DBAPI
> > >> module.
> > >> > >> > I do have access to lots and lots of different Sybase stuff so I
> > >> will
> > >> > >> > start from your patched version and reintegrate my schema
> > >> > >> > introspection and other stuff. Do you have a ticket open for the
> > >> > >> > sybase driver yet? Where should I send the patches?
>
> > >> > >> > pjjH
>
> > >> > >> > def do_execute(self, cursor, statement, parameters,
> > >> context=None,
> > >> > >> > **kwargs):
> > >> > >> > if self.paramstyle == 'named':
> > >> > >> > #prepend the arguments with an '@'
> > >> > >> > hacked_args = dict(("@"+n, v) for n,v in
> > >> parameters.items
> > >> > >> > ())
> > >> > >> > super(SybaseSQLDialect_Sybase,
> > >> self).do_execute(cursor,
> > >> > >> > statement, hacked_args, context=context, **kwargs)
> > >> > >> > else:
> > >> > >> > super(SybaseSQLDialect_Sybase,
> > >> self).do_execute(cursor,
> > >> > >> > statement, parameters, context=context, **kwargs)
>
> > >> > >> > def create_connect_args(self, url):
> > >> > >> > opts = url.translate_connect_args()
> > >> > >> > opts.update(url.query)
>
> > >> > >> > self.autocommit = False
> > >> > >> > if 'autocommit' in opts:
> > >> > >> > self.autocommit = bool(int(opts.pop('autocommit')))
>
> > >> > >> > dictArgs = {
> > >> > >> > 'datetime' : 'python', # Stop the annoying
> > >> > >> > diagnostics from the module
> > >> > >> > 'auto_commit' : self.autocommit, # the named argument
> > >> is
> > >> > >> > called 'auto_commit' rather than 'autocommit'
> > >> > >> > }
>
> > >> > >> > if 'database' in opts:
> > >> > >> > dictArgs['database'] = opts['database']
>
> > >> > >> > return ([opts['host'], opts['username'],
> > >> opts['password']],
> > >> > >> > dictArgs)
>
> > >> > >> > On Feb 26, 4:30 pm, Michael Bayer <mike...@zzzcomputing.com>
> > >> wrote:
> > >> > >> >> On Feb 26, 2009, at 3:55 PM, phrrn...@googlemail.com wrote:
>
> > >> > >> >>> I am doing some work on a SA engine for Sybase Adaptive Server
> > >> > >> >>> Enterprise (ASE) on top of both pyodbc and the Sybase DB-API
> > >> driver.
> > >> > >> >>> The existing sybase engine for SA only works with Sybase
> > >> Anywhere
> > >> > >> >>> (ASA).
>
> > >> > >> >> that is correct ; I've recently had to take a look at this
> > >> driver and
> > >> > >> >> realized that it was not really written for Sybase at all, and
> > >> the
> > >> > >> >> original author is whereabouts unknown. To that end I would
> > >> like it
> > >> > >> >> to be replaced with an actual Sybase driver.
>
> > >> > >> >>> There is a problem with named parameters with the Sybase driver
> > >> in
>
> ...
>
> read more ยป
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