from sphinx.application import TemplateBridge
-from sphinx.builder import StandaloneHTMLBuilder
+from sphinx.builders.html import StandaloneHTMLBuilder
from sphinx.highlighting import PygmentsBridge
from pygments import highlight
from pygments.lexer import RegexLexer, bygroups, using
def format(self, tokensource, outfile):
LatexFormatter.format(self, self._filter_tokens(tokensource), outfile)
+def autodoc_skip_member(app, what, name, obj, skip, options):
+ if what == 'class' and skip and name == '__init__':
+ return False
+ else:
+ return skip
+
def setup(app):
app.add_lexer('pycon+sql', PyConWithSQLLexer())
app.add_lexer('python+sql', PythonWithSQLLexer())
+ app.connect('autodoc-skip-member', autodoc_skip_member)
PygmentsBridge.html_formatter = PopupSQLFormatter
PygmentsBridge.latex_formatter = PopupLatexFormatter
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
+"""Support for the SQLite database.
+
+Driver
+------
+
+When using Python 2.5 and above, the built in ``sqlite3`` driver is
+already installed and no additional installation is needed. Otherwise,
+the ``pysqlite2`` driver needs to be present. This is the same driver as
+``sqlite3``, just with a different name.
+
+The ``pysqlite2`` driver will be loaded first, and if not found, ``sqlite3``
+is loaded. This allows an explicitly installed pysqlite driver to take
+precedence over the built in one. As with all dialects, a specific
+DBAPI module may be provided to :func:`~sqlalchemy.create_engine()` to control
+this explicitly::
+
+ from sqlite3 import dbapi2 as sqlite
+ e = create_engine('sqlite:///file.db', module=sqlite)
+
+Full documentation on pysqlite is available at:
+`<http://www.initd.org/pub/software/pysqlite/doc/usage-guide.html>`_
+
+Connect Strings
+---------------
+
+The file specification for the SQLite database is taken as the "database" portion of
+the URL. Note that the format of a url is::
+
+ driver://user:pass@host/database
+
+This means that the actual filename to be used starts with the characters to the
+**right** of the third slash. So connecting to a relative filepath looks like::
+
+ # relative path
+ e = create_engine('sqlite:///path/to/database.db')
+
+An absolute path, which is denoted by starting with a slash, means you need **four**
+slashes::
+
+ # absolute path
+ e = create_engine('sqlite:////path/to/database.db')
+
+To use a Windows path, regular drive specifications and backslashes can be used.
+Double backslashes are probably needed::
+
+ # absolute path on Windows
+ e = create_engine('sqlite:///C:\\\\path\\\\to\\\\database.db')
+
+The sqlite ``:memory:`` identifier is the default if no filepath is present. Specify
+``sqlite://`` and nothing else::
+
+ # in-memory database
+ e = create_engine('sqlite://')
+
+Threading Behavior
+------------------
+
+Pysqlite connections do not support being moved between threads, unless
+the ``check_same_thread`` Pysqlite flag is set to ``False``. In addition,
+when using an in-memory SQLite database, the full database exists only within
+the scope of a single connection. It is reported that an in-memory
+database does not support being shared between threads regardless of the
+``check_same_thread`` flag - which means that a multithreaded
+application **cannot** share data from a ``:memory:`` database across threads
+unless access to the connection is limited to a single worker thread which communicates
+through a queueing mechanism to concurrent threads.
+
+To provide a default which accomodates SQLite's default threading capabilities
+somewhat reasonably, the SQLite dialect will specify that the :class:`~sqlalchemy.pool.SingletonThreadPool`
+be used by default. This pool maintains a single SQLite connection per thread
+that is held open up to a count of five concurrent threads. When more than five threads
+are used, a cleanup mechanism will dispose of excess unused connections.
+
+Two optional pool implementations that may be appropriate for particular SQLite usage scenarios:
+
+ * the :class:`sqlalchemy.pool.StaticPool` might be appropriate for a multithreaded
+ application using an in-memory database, assuming the threading issues inherent in
+ pysqlite are somehow accomodated for. This pool holds persistently onto a single connection
+ which is never closed, and is returned for all requests.
+
+ * the :class:`sqlalchemy.pool.NullPool` might be appropriate for an application that
+ makes use of a file-based sqlite database. This pool disables any actual "pooling"
+ behavior, and simply opens and closes real connections corresonding to the :func:`connect()`
+ and :func:`close()` methods. SQLite can "connect" to a particular file with very high
+ efficiency, so this option may actually perform better without the extra overhead
+ of :class:`SingletonThreadPool`. NullPool will of course render a ``:memory:`` connection
+ useless since the database would be lost as soon as the connection is "returned" to the pool.
+
+Date and Time Types
+-------------------
+
+SQLite does not have built-in DATE, TIME, or DATETIME types, and pysqlite does not provide
+out of the box functionality for translating values between Python `datetime` objects
+and a SQLite-supported format. SQLAlchemy's own :class:`~sqlalchemy.types.DateTime`
+and related types provide date formatting and parsing functionality when SQlite is used.
+The implementation classes are :class:`SLDateTime`, :class:`SLDate` and :class:`SLTime`.
+These types represent dates and times as ISO formatted strings, which also nicely
+support ordering. There's no reliance on typical "libc" internals for these functions
+so historical dates are fully supported.
+
+Unicode
+-------
+
+In contrast to SQLAlchemy's active handling of date and time types for pysqlite, pysqlite's
+default behavior regarding Unicode is that all strings are returned as Python unicode objects
+in all cases. So even if the :class:`~sqlalchemy.types.Unicode` type is
+*not* used, you will still always receive unicode data back from a result set. It is
+**strongly** recommended that you do use the :class:`~sqlalchemy.types.Unicode` type
+to represent strings, since it will raise a warning if a non-unicode Python string is
+passed from the user application. Mixing the usage of non-unicode objects with returned unicode objects can
+quickly create confusion, particularly when using the ORM as internal data is not
+always represented by an actual database result string.
+
+"""
+
import datetime, re, time
Instead it literally opens and closes the underlying DB-API connection
per each connection open/close.
+ Reconnect-related functions such as ``recycle`` and connection
+ invalidation are not supported by this Pool implementation, since
+ no connections are held persistently.
+
"""
def status(self):
return self.create_connection()
class StaticPool(Pool):
- """A Pool of exactly one connection, used for all requests."""
+ """A Pool of exactly one connection, used for all requests.
+
+ Reconnect-related functions such as ``recycle`` and connection
+ invalidation (which is also used to support auto-reconnect) are not
+ currently supported by this Pool implementation but may be implemented
+ in a future release.
+
+ """
def __init__(self, creator, **params):
"""
connection object. The function will be called with
parameters.
- :param recycle: If set to non -1, number of seconds between
- connection recycling, which means upon checkout, if this
- timeout is surpassed the connection will be closed and
- replaced with a newly opened connection. Defaults to -1.
-
:param echo: If True, connections being pulled and retrieved
from the pool will be logged to the standard output, as well
as pool sizing information. Echoing can also be achieved by
enabling logging for the "sqlalchemy.pool"
namespace. Defaults to False.
- :param use_threadlocal: If set to True, repeated calls to
- :meth:`connect` within the same application thread will be
- guaranteed to return the same connection object, if one has
- already been retrieved from the pool and has not been
- returned yet. Offers a slight performance advantage at the
- cost of individual transactions by default. The
- :meth:`unique_connection` method is provided to bypass the
- threadlocal behavior installed into :meth:`connect`.
-
:param reset_on_return: If true, reset the database state of
connections returned to the pool. This is typically a
ROLLBACK to release locks and transaction resources.
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
