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Microsoft SQL Server
— SQLAlchemy 0.6.8 Documentation</title>
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<h1>SQLAlchemy 0.6.8 Documentation</h1>
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Version: <span class="versionnum">0.6.8</span> Last Updated: 06/05/2011 13:10:26
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Microsoft SQL Server
<h2>
Microsoft SQL Server
</h2>
<ul>
<li><a class="reference internal" href="#">Microsoft SQL Server</a><ul>
<li><a class="reference internal" href="#connecting">Connecting</a></li>
<li><a class="reference internal" href="#auto-increment-behavior">Auto Increment Behavior</a></li>
<li><a class="reference internal" href="#collation-support">Collation Support</a></li>
<li><a class="reference internal" href="#limit-offset-support">LIMIT/OFFSET Support</a></li>
<li><a class="reference internal" href="#nullability">Nullability</a></li>
<li><a class="reference internal" href="#date-time-handling">Date / Time Handling</a></li>
<li><a class="reference internal" href="#compatibility-levels">Compatibility Levels</a></li>
<li><a class="reference internal" href="#triggers">Triggers</a></li>
<li><a class="reference internal" href="#enabling-snapshot-isolation">Enabling Snapshot Isolation</a></li>
<li><a class="reference internal" href="#known-issues">Known Issues</a></li>
<li><a class="reference internal" href="#sql-server-data-types">SQL Server Data Types</a></li>
<li><a class="reference internal" href="#module-sqlalchemy.dialects.mssql.pyodbc">PyODBC</a><ul>
<li><a class="reference internal" href="#id1">Connecting</a></li>
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<li><a class="reference internal" href="#id2">Connecting</a></li>
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<li><a class="reference internal" href="#id4">Connecting</a></li>
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<div class="section" id="module-sqlalchemy.dialects.mssql.base">
<span id="microsoft-sql-server"></span><h1>Microsoft SQL Server<a class="headerlink" href="#module-sqlalchemy.dialects.mssql.base" title="Permalink to this headline">¶</a></h1>
<p>Support for the Microsoft SQL Server database.</p>
<div class="section" id="connecting">
<h2>Connecting<a class="headerlink" href="#connecting" title="Permalink to this headline">¶</a></h2>
<p>See the individual driver sections below for details on connecting.</p>
</div>
<div class="section" id="auto-increment-behavior">
<h2>Auto Increment Behavior<a class="headerlink" href="#auto-increment-behavior" title="Permalink to this headline">¶</a></h2>
<p><tt class="docutils literal"><span class="pre">IDENTITY</span></tt> columns are supported by using SQLAlchemy
<tt class="docutils literal"><span class="pre">schema.Sequence()</span></tt> objects. In other words:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="kn">import</span> <span class="n">Table</span><span class="p">,</span> <span class="n">Integer</span><span class="p">,</span> <span class="n">Sequence</span><span class="p">,</span> <span class="n">Column</span>
<span class="n">Table</span><span class="p">(</span><span class="s">'test'</span><span class="p">,</span> <span class="n">metadata</span><span class="p">,</span>
<span class="n">Column</span><span class="p">(</span><span class="s">'id'</span><span class="p">,</span> <span class="n">Integer</span><span class="p">,</span>
<span class="n">Sequence</span><span class="p">(</span><span class="s">'blah'</span><span class="p">,</span><span class="mi">100</span><span class="p">,</span><span class="mi">10</span><span class="p">),</span> <span class="n">primary_key</span><span class="o">=</span><span class="bp">True</span><span class="p">),</span>
<span class="n">Column</span><span class="p">(</span><span class="s">'name'</span><span class="p">,</span> <span class="n">String</span><span class="p">(</span><span class="mi">20</span><span class="p">))</span>
<span class="p">)</span><span class="o">.</span><span class="n">create</span><span class="p">(</span><span class="n">some_engine</span><span class="p">)</span></pre></div>
</div>
<p>would yield:</p>
<div class="highlight-python"><pre>CREATE TABLE test (
id INTEGER NOT NULL IDENTITY(100,10) PRIMARY KEY,
name VARCHAR(20) NULL,
)</pre>
</div>
<p>Note that the <tt class="docutils literal"><span class="pre">start</span></tt> and <tt class="docutils literal"><span class="pre">increment</span></tt> values for sequences are
optional and will default to 1,1.</p>
<p>Implicit <tt class="docutils literal"><span class="pre">autoincrement</span></tt> behavior works the same in MSSQL as it
does in other dialects and results in an <tt class="docutils literal"><span class="pre">IDENTITY</span></tt> column.</p>
<ul class="simple">
<li>Support for <tt class="docutils literal"><span class="pre">SET</span> <span class="pre">IDENTITY_INSERT</span> <span class="pre">ON</span></tt> mode (automagic on / off for
<tt class="docutils literal"><span class="pre">INSERT</span></tt> s)</li>
<li>Support for auto-fetching of <tt class="docutils literal"><span class="pre">@@IDENTITY/@@SCOPE_IDENTITY()</span></tt> on
<tt class="docutils literal"><span class="pre">INSERT</span></tt></li>
</ul>
</div>
<div class="section" id="collation-support">
<h2>Collation Support<a class="headerlink" href="#collation-support" title="Permalink to this headline">¶</a></h2>
<p>MSSQL specific string types support a collation parameter that
creates a column-level specific collation for the column. The
collation parameter accepts a Windows Collation Name or a SQL
Collation Name. Supported types are MSChar, MSNChar, MSString,
MSNVarchar, MSText, and MSNText. For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">sqlalchemy.dialects.mssql</span> <span class="kn">import</span> <span class="n">VARCHAR</span>
<span class="n">Column</span><span class="p">(</span><span class="s">'login'</span><span class="p">,</span> <span class="n">VARCHAR</span><span class="p">(</span><span class="mi">32</span><span class="p">,</span> <span class="n">collation</span><span class="o">=</span><span class="s">'Latin1_General_CI_AS'</span><span class="p">))</span></pre></div>
</div>
<p>When such a column is associated with a <tt class="xref py py-class docutils literal"><span class="pre">Table</span></tt>, the
CREATE TABLE statement for this column will yield:</p>
<div class="highlight-python"><pre>login VARCHAR(32) COLLATE Latin1_General_CI_AS NULL</pre>
</div>
</div>
<div class="section" id="limit-offset-support">
<h2>LIMIT/OFFSET Support<a class="headerlink" href="#limit-offset-support" title="Permalink to this headline">¶</a></h2>
<p>MSSQL has no support for the LIMIT or OFFSET keysowrds. LIMIT is
supported directly through the <tt class="docutils literal"><span class="pre">TOP</span></tt> Transact SQL keyword:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">select</span><span class="o">.</span><span class="n">limit</span></pre></div>
</div>
<p>will yield:</p>
<div class="highlight-python"><pre>SELECT TOP n</pre>
</div>
<p>If using SQL Server 2005 or above, LIMIT with OFFSET
support is available through the <tt class="docutils literal"><span class="pre">ROW_NUMBER</span> <span class="pre">OVER</span></tt> construct.
For versions below 2005, LIMIT with OFFSET usage will fail.</p>
</div>
<div class="section" id="nullability">
<h2>Nullability<a class="headerlink" href="#nullability" title="Permalink to this headline">¶</a></h2>
<p>MSSQL has support for three levels of column nullability. The default
nullability allows nulls and is explicit in the CREATE TABLE
construct:</p>
<div class="highlight-python"><pre>name VARCHAR(20) NULL</pre>
</div>
<p>If <tt class="docutils literal"><span class="pre">nullable=None</span></tt> is specified then no specification is made. In
other words the database’s configured default is used. This will
render:</p>
<div class="highlight-python"><pre>name VARCHAR(20)</pre>
</div>
<p>If <tt class="docutils literal"><span class="pre">nullable</span></tt> is <tt class="xref docutils literal"><span class="pre">True</span></tt> or <tt class="xref docutils literal"><span class="pre">False</span></tt> then the column will be
<tt class="docutils literal"><span class="pre">NULL`</span> <span class="pre">or</span> <span class="pre">``NOT</span> <span class="pre">NULL</span></tt> respectively.</p>
</div>
<div class="section" id="date-time-handling">
<h2>Date / Time Handling<a class="headerlink" href="#date-time-handling" title="Permalink to this headline">¶</a></h2>
<p>DATE and TIME are supported. Bind parameters are converted
to datetime.datetime() objects as required by most MSSQL drivers,
and results are processed from strings if needed.
The DATE and TIME types are not available for MSSQL 2005 and
previous - if a server version below 2008 is detected, DDL
for these types will be issued as DATETIME.</p>
</div>
<div class="section" id="compatibility-levels">
<h2>Compatibility Levels<a class="headerlink" href="#compatibility-levels" title="Permalink to this headline">¶</a></h2>
<p>MSSQL supports the notion of setting compatibility levels at the
database level. This allows, for instance, to run a database that
is compatibile with SQL2000 while running on a SQL2005 database
server. <tt class="docutils literal"><span class="pre">server_version_info</span></tt> will always return the database
server version information (in this case SQL2005) and not the
compatibiility level information. Because of this, if running under
a backwards compatibility mode SQAlchemy may attempt to use T-SQL
statements that are unable to be parsed by the database server.</p>
</div>
<div class="section" id="triggers">
<h2>Triggers<a class="headerlink" href="#triggers" title="Permalink to this headline">¶</a></h2>
<p>SQLAlchemy by default uses OUTPUT INSERTED to get at newly
generated primary key values via IDENTITY columns or other
server side defaults. MS-SQL does not
allow the usage of OUTPUT INSERTED on tables that have triggers.
To disable the usage of OUTPUT INSERTED on a per-table basis,
specify <tt class="docutils literal"><span class="pre">implicit_returning=False</span></tt> for each <a class="reference internal" href="../core/schema.html#sqlalchemy.schema.Table" title="sqlalchemy.schema.Table"><tt class="xref py py-class docutils literal"><span class="pre">Table</span></tt></a>
which has triggers:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">Table</span><span class="p">(</span><span class="s">'mytable'</span><span class="p">,</span> <span class="n">metadata</span><span class="p">,</span>
<span class="n">Column</span><span class="p">(</span><span class="s">'id'</span><span class="p">,</span> <span class="n">Integer</span><span class="p">,</span> <span class="n">primary_key</span><span class="o">=</span><span class="bp">True</span><span class="p">),</span>
<span class="c"># ...,</span>
<span class="n">implicit_returning</span><span class="o">=</span><span class="bp">False</span>
<span class="p">)</span></pre></div>
</div>
<p>Declarative form:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">class</span> <span class="nc">MyClass</span><span class="p">(</span><span class="n">Base</span><span class="p">):</span>
<span class="c"># ...</span>
<span class="n">__table_args__</span> <span class="o">=</span> <span class="p">{</span><span class="s">'implicit_returning'</span><span class="p">:</span><span class="bp">False</span><span class="p">}</span></pre></div>
</div>
<p>This option can also be specified engine-wide using the
<tt class="docutils literal"><span class="pre">implicit_returning=False</span></tt> argument on <a class="reference internal" href="../core/engines.html#sqlalchemy.create_engine" title="sqlalchemy.create_engine"><tt class="xref py py-func docutils literal"><span class="pre">create_engine()</span></tt></a>.</p>
</div>
<div class="section" id="enabling-snapshot-isolation">
<h2>Enabling Snapshot Isolation<a class="headerlink" href="#enabling-snapshot-isolation" title="Permalink to this headline">¶</a></h2>
<p>Not necessarily specific to SQLAlchemy, SQL Server has a default transaction
isolation mode that locks entire tables, and causes even mildly concurrent
applications to have long held locks and frequent deadlocks.
Enabling snapshot isolation for the database as a whole is recommended
for modern levels of concurrency support. This is accomplished via the
following ALTER DATABASE commands executed at the SQL prompt:</p>
<div class="highlight-python"><pre>ALTER DATABASE MyDatabase SET ALLOW_SNAPSHOT_ISOLATION ON
ALTER DATABASE MyDatabase SET READ_COMMITTED_SNAPSHOT ON</pre>
</div>
<p>Background on SQL Server snapshot isolation is available at
<a class="reference external" href="http://msdn.microsoft.com/en-us/library/ms175095.aspx">http://msdn.microsoft.com/en-us/library/ms175095.aspx</a>.</p>
</div>
<div class="section" id="known-issues">
<h2>Known Issues<a class="headerlink" href="#known-issues" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li>No support for more than one <tt class="docutils literal"><span class="pre">IDENTITY</span></tt> column per table</li>
<li>reflection of indexes does not work with versions older than
SQL Server 2005</li>
</ul>
</div>
<div class="section" id="sql-server-data-types">
<h2>SQL Server Data Types<a class="headerlink" href="#sql-server-data-types" title="Permalink to this headline">¶</a></h2>
<p>As with all SQLAlchemy dialects, all UPPERCASE types that are known to be
valid with SQL server are importable from the top level dialect, whether
they originate from <a class="reference internal" href="../core/types.html#module-sqlalchemy.types" title="sqlalchemy.types"><tt class="xref py py-mod docutils literal"><span class="pre">sqlalchemy.types</span></tt></a> or from the local dialect:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">sqlalchemy.dialects.mssql</span> <span class="kn">import</span> \
<span class="n">BIGINT</span><span class="p">,</span> <span class="n">BINARY</span><span class="p">,</span> <span class="n">BIT</span><span class="p">,</span> <span class="n">CHAR</span><span class="p">,</span> <span class="n">DATE</span><span class="p">,</span> <span class="n">DATETIME</span><span class="p">,</span> <span class="n">DATETIME2</span><span class="p">,</span> \
<span class="n">DATETIMEOFFSET</span><span class="p">,</span> <span class="n">DECIMAL</span><span class="p">,</span> <span class="n">FLOAT</span><span class="p">,</span> <span class="n">IMAGE</span><span class="p">,</span> <span class="n">INTEGER</span><span class="p">,</span> <span class="n">MONEY</span><span class="p">,</span> \
<span class="n">NCHAR</span><span class="p">,</span> <span class="n">NTEXT</span><span class="p">,</span> <span class="n">NUMERIC</span><span class="p">,</span> <span class="n">NVARCHAR</span><span class="p">,</span> <span class="n">REAL</span><span class="p">,</span> <span class="n">SMALLDATETIME</span><span class="p">,</span> \
<span class="n">SMALLINT</span><span class="p">,</span> <span class="n">SMALLMONEY</span><span class="p">,</span> <span class="n">SQL_VARIANT</span><span class="p">,</span> <span class="n">TEXT</span><span class="p">,</span> <span class="n">TIME</span><span class="p">,</span> \
<span class="n">TIMESTAMP</span><span class="p">,</span> <span class="n">TINYINT</span><span class="p">,</span> <span class="n">UNIQUEIDENTIFIER</span><span class="p">,</span> <span class="n">VARBINARY</span><span class="p">,</span> <span class="n">VARCHAR</span></pre></div>
</div>
<p>Types which are specific to SQL Server, or have SQL Server-specific
construction arguments, are as follows:</p>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.BIT">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">BIT</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.BIT" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.TypeEngine" title="sqlalchemy.types.TypeEngine"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TypeEngine</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.BIT.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.BIT.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.CHAR">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">CHAR</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.CHAR" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._StringType</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.CHAR" title="sqlalchemy.types.CHAR"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.CHAR</span></tt></a></p>
<p>MSSQL CHAR type, for fixed-length non-Unicode data with a maximum
of 8,000 characters.</p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.CHAR.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.CHAR.__init__" title="Permalink to this definition">¶</a></dt>
<dd><p>Construct a CHAR.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>length</strong> – Optinal, maximum data length, in characters.</li>
<li><strong>convert_unicode</strong> – <p>defaults to False. If True, convert
<tt class="docutils literal"><span class="pre">unicode</span></tt> data sent to the database to a <tt class="docutils literal"><span class="pre">str</span></tt>
bytestring, and convert bytestrings coming back from the
database into <tt class="docutils literal"><span class="pre">unicode</span></tt>.</p>
<p>Bytestrings are encoded using the dialect’s
<tt class="xref py py-attr docutils literal"><span class="pre">encoding</span></tt>, which
defaults to <cite>utf-8</cite>.</p>
<p>If False, may be overridden by
<tt class="xref py py-attr docutils literal"><span class="pre">sqlalchemy.engine.base.Dialect.convert_unicode</span></tt>.</p>
</li>
<li><strong>collation</strong> – Optional, a column-level collation for this string
value. Accepts a Windows Collation Name or a SQL Collation Name.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.DATETIME2">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">DATETIME2</tt><big>(</big><em>precision=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.DATETIME2" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._DateTimeBase</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.DateTime" title="sqlalchemy.types.DateTime"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.DateTime</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.DATETIME2.__init__">
<tt class="descname">__init__</tt><big>(</big><em>precision=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.DATETIME2.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.DATETIMEOFFSET">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">DATETIMEOFFSET</tt><big>(</big><em>precision=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.DATETIMEOFFSET" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.TypeEngine" title="sqlalchemy.types.TypeEngine"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TypeEngine</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.DATETIMEOFFSET.__init__">
<tt class="descname">__init__</tt><big>(</big><em>precision=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.DATETIMEOFFSET.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.IMAGE">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">IMAGE</tt><big>(</big><em>length=None</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.IMAGE" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.LargeBinary" title="sqlalchemy.types.LargeBinary"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.LargeBinary</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.IMAGE.__init__">
<tt class="descname">__init__</tt><big>(</big><em>length=None</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.IMAGE.__init__" title="Permalink to this definition">¶</a></dt>
<dd><p>Construct a LargeBinary type.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><strong>length</strong> – optional, a length for the column for use in
DDL statements, for those BLOB types that accept a length
(i.e. MySQL). It does <em>not</em> produce a small BINARY/VARBINARY
type - use the BINARY/VARBINARY types specifically for those.
May be safely omitted if no <tt class="docutils literal"><span class="pre">CREATE</span>
<span class="pre">TABLE</span></tt> will be issued. Certain databases may require a
<em>length</em> for use in DDL, and will raise an exception when
the <tt class="docutils literal"><span class="pre">CREATE</span> <span class="pre">TABLE</span></tt> DDL is issued.</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.MONEY">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">MONEY</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.MONEY" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.TypeEngine" title="sqlalchemy.types.TypeEngine"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TypeEngine</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.MONEY.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.MONEY.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.NCHAR">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">NCHAR</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.NCHAR" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._StringType</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.NCHAR" title="sqlalchemy.types.NCHAR"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.NCHAR</span></tt></a></p>
<p>MSSQL NCHAR type.</p>
<p>For fixed-length unicode character data up to 4,000 characters.</p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.NCHAR.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.NCHAR.__init__" title="Permalink to this definition">¶</a></dt>
<dd><p>Construct an NCHAR.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>length</strong> – Optional, Maximum data length, in characters.</li>
<li><strong>collation</strong> – Optional, a column-level collation for this string
value. Accepts a Windows Collation Name or a SQL Collation Name.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.NTEXT">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">NTEXT</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.NTEXT" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._StringType</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.UnicodeText" title="sqlalchemy.types.UnicodeText"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.UnicodeText</span></tt></a></p>
<p>MSSQL NTEXT type, for variable-length unicode text up to 2^30
characters.</p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.NTEXT.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.NTEXT.__init__" title="Permalink to this definition">¶</a></dt>
<dd><p>Construct a NTEXT.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><strong>collation</strong> – Optional, a column-level collation for this string
value. Accepts a Windows Collation Name or a SQL Collation Name.</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.NVARCHAR">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">NVARCHAR</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.NVARCHAR" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._StringType</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.NVARCHAR" title="sqlalchemy.types.NVARCHAR"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.NVARCHAR</span></tt></a></p>
<p>MSSQL NVARCHAR type.</p>
<p>For variable-length unicode character data up to 4,000 characters.</p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.NVARCHAR.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.NVARCHAR.__init__" title="Permalink to this definition">¶</a></dt>
<dd><p>Construct a NVARCHAR.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>length</strong> – Optional, Maximum data length, in characters.</li>
<li><strong>collation</strong> – Optional, a column-level collation for this string
value. Accepts a Windows Collation Name or a SQL Collation Name.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.REAL">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">REAL</tt><a class="headerlink" href="#sqlalchemy.dialects.mssql.REAL" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.Float" title="sqlalchemy.types.Float"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.Float</span></tt></a></p>
<p>A type for <tt class="docutils literal"><span class="pre">real</span></tt> numbers.</p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.REAL.__init__">
<tt class="descname">__init__</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.REAL.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.SMALLDATETIME">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">SMALLDATETIME</tt><big>(</big><em>timezone=False</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.SMALLDATETIME" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._DateTimeBase</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.DateTime" title="sqlalchemy.types.DateTime"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.DateTime</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.SMALLDATETIME.__init__">
<tt class="descname">__init__</tt><big>(</big><em>timezone=False</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.SMALLDATETIME.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.SMALLMONEY">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">SMALLMONEY</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.SMALLMONEY" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.TypeEngine" title="sqlalchemy.types.TypeEngine"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TypeEngine</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.SMALLMONEY.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.SMALLMONEY.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.SQL_VARIANT">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">SQL_VARIANT</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.SQL_VARIANT" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.TypeEngine" title="sqlalchemy.types.TypeEngine"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TypeEngine</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.SQL_VARIANT.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.SQL_VARIANT.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.TEXT">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">TEXT</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.TEXT" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._StringType</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.TEXT" title="sqlalchemy.types.TEXT"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TEXT</span></tt></a></p>
<p>MSSQL TEXT type, for variable-length text up to 2^31 characters.</p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.TEXT.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.TEXT.__init__" title="Permalink to this definition">¶</a></dt>
<dd><p>Construct a TEXT.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><strong>collation</strong> – Optional, a column-level collation for this string
value. Accepts a Windows Collation Name or a SQL Collation Name.</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.TIME">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">TIME</tt><big>(</big><em>precision=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.TIME" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.TIME" title="sqlalchemy.types.TIME"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TIME</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.TIME.__init__">
<tt class="descname">__init__</tt><big>(</big><em>precision=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.TIME.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.TINYINT">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">TINYINT</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.TINYINT" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.Integer" title="sqlalchemy.types.Integer"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.Integer</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.TINYINT.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.TINYINT.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.UNIQUEIDENTIFIER">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">UNIQUEIDENTIFIER</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.UNIQUEIDENTIFIER" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="../core/types.html#sqlalchemy.types.TypeEngine" title="sqlalchemy.types.TypeEngine"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.TypeEngine</span></tt></a></p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.UNIQUEIDENTIFIER.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.UNIQUEIDENTIFIER.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.dialects.mssql.VARCHAR">
<em class="property">class </em><tt class="descclassname">sqlalchemy.dialects.mssql.</tt><tt class="descname">VARCHAR</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.VARCHAR" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.dialects.mssql.base._StringType</span></tt>, <a class="reference internal" href="../core/types.html#sqlalchemy.types.VARCHAR" title="sqlalchemy.types.VARCHAR"><tt class="xref py py-class docutils literal"><span class="pre">sqlalchemy.types.VARCHAR</span></tt></a></p>
<p>MSSQL VARCHAR type, for variable-length non-Unicode data with a maximum
of 8,000 characters.</p>
<dl class="method">
<dt id="sqlalchemy.dialects.mssql.VARCHAR.__init__">
<tt class="descname">__init__</tt><big>(</big><em>*args</em>, <em>**kw</em><big>)</big><a class="headerlink" href="#sqlalchemy.dialects.mssql.VARCHAR.__init__" title="Permalink to this definition">¶</a></dt>
<dd><p>Construct a VARCHAR.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>length</strong> – Optinal, maximum data length, in characters.</li>
<li><strong>convert_unicode</strong> – <p>defaults to False. If True, convert
<tt class="docutils literal"><span class="pre">unicode</span></tt> data sent to the database to a <tt class="docutils literal"><span class="pre">str</span></tt>
bytestring, and convert bytestrings coming back from the
database into <tt class="docutils literal"><span class="pre">unicode</span></tt>.</p>
<p>Bytestrings are encoded using the dialect’s
<tt class="xref py py-attr docutils literal"><span class="pre">encoding</span></tt>, which
defaults to <cite>utf-8</cite>.</p>
<p>If False, may be overridden by
<tt class="xref py py-attr docutils literal"><span class="pre">sqlalchemy.engine.base.Dialect.convert_unicode</span></tt>.</p>
</li>
<li><strong>collation</strong> – Optional, a column-level collation for this string
value. Accepts a Windows Collation Name or a SQL Collation Name.</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
</div>
<div class="section" id="module-sqlalchemy.dialects.mssql.pyodbc">
<span id="pyodbc"></span><h2>PyODBC<a class="headerlink" href="#module-sqlalchemy.dialects.mssql.pyodbc" title="Permalink to this headline">¶</a></h2>
<p>Support for MS-SQL via pyodbc.</p>
<p>pyodbc is available at:</p>
<blockquote>
<div><a class="reference external" href="http://pypi.python.org/pypi/pyodbc/">http://pypi.python.org/pypi/pyodbc/</a></div></blockquote>
<div class="section" id="id1">
<h3>Connecting<a class="headerlink" href="#id1" title="Permalink to this headline">¶</a></h3>
<p>Examples of pyodbc connection string URLs:</p>
<ul>
<li><p class="first"><tt class="docutils literal"><span class="pre">mssql+pyodbc://mydsn</span></tt> - connects using the specified DSN named <tt class="docutils literal"><span class="pre">mydsn</span></tt>.
The connection string that is created will appear like:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">dsn</span><span class="o">=</span><span class="n">mydsn</span><span class="p">;</span><span class="n">Trusted_Connection</span><span class="o">=</span><span class="n">Yes</span></pre></div>
</div>
</li>
<li><p class="first"><tt class="docutils literal"><span class="pre">mssql+pyodbc://user:pass@mydsn</span></tt> - connects using the DSN named
<tt class="docutils literal"><span class="pre">mydsn</span></tt> passing in the <tt class="docutils literal"><span class="pre">UID</span></tt> and <tt class="docutils literal"><span class="pre">PWD</span></tt> information. The
connection string that is created will appear like:</p>
<div class="highlight-python"><pre>dsn=mydsn;UID=user;PWD=pass</pre>
</div>
</li>
<li><p class="first"><tt class="docutils literal"><span class="pre">mssql+pyodbc://user:pass@mydsn/?LANGUAGE=us_english</span></tt> - connects
using the DSN named <tt class="docutils literal"><span class="pre">mydsn</span></tt> passing in the <tt class="docutils literal"><span class="pre">UID</span></tt> and <tt class="docutils literal"><span class="pre">PWD</span></tt>
information, plus the additional connection configuration option
<tt class="docutils literal"><span class="pre">LANGUAGE</span></tt>. The connection string that is created will appear
like:</p>
<div class="highlight-python"><pre>dsn=mydsn;UID=user;PWD=pass;LANGUAGE=us_english</pre>
</div>
</li>
<li><p class="first"><tt class="docutils literal"><span class="pre">mssql+pyodbc://user:pass@host/db</span></tt> - connects using a connection string
dynamically created that would appear like:</p>
<div class="highlight-python"><pre>DRIVER={SQL Server};Server=host;Database=db;UID=user;PWD=pass</pre>
</div>
</li>
<li><p class="first"><tt class="docutils literal"><span class="pre">mssql+pyodbc://user:pass@host:123/db</span></tt> - connects using a connection
string that is dynamically created, which also includes the port
information using the comma syntax. If your connection string
requires the port information to be passed as a <tt class="docutils literal"><span class="pre">port</span></tt> keyword
see the next example. This will create the following connection
string:</p>
<div class="highlight-python"><pre>DRIVER={SQL Server};Server=host,123;Database=db;UID=user;PWD=pass</pre>
</div>
</li>
<li><p class="first"><tt class="docutils literal"><span class="pre">mssql+pyodbc://user:pass@host/db?port=123</span></tt> - connects using a connection
string that is dynamically created that includes the port
information as a separate <tt class="docutils literal"><span class="pre">port</span></tt> keyword. This will create the
following connection string:</p>
<div class="highlight-python"><pre>DRIVER={SQL Server};Server=host;Database=db;UID=user;PWD=pass;port=123</pre>
</div>
</li>
</ul>
<p>If you require a connection string that is outside the options
presented above, use the <tt class="docutils literal"><span class="pre">odbc_connect</span></tt> keyword to pass in a
urlencoded connection string. What gets passed in will be urldecoded
and passed directly.</p>
<p>For example:</p>
<div class="highlight-python"><pre>mssql+pyodbc:///?odbc_connect=dsn%3Dmydsn%3BDatabase%3Ddb</pre>
</div>
<p>would create the following connection string:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">dsn</span><span class="o">=</span><span class="n">mydsn</span><span class="p">;</span><span class="n">Database</span><span class="o">=</span><span class="n">db</span></pre></div>
</div>
<p>Encoding your connection string can be easily accomplished through
the python shell. For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">urllib</span>
<span class="gp">>>> </span><span class="n">urllib</span><span class="o">.</span><span class="n">quote_plus</span><span class="p">(</span><span class="s">'dsn=mydsn;Database=db'</span><span class="p">)</span>
<span class="go">'dsn%3Dmydsn%3BDatabase%3Ddb'</span></pre></div>
</div>
</div>
</div>
<div class="section" id="module-sqlalchemy.dialects.mssql.mxodbc">
<span id="mxodbc"></span><h2>mxODBC<a class="headerlink" href="#module-sqlalchemy.dialects.mssql.mxodbc" title="Permalink to this headline">¶</a></h2>
<p>Support for MS-SQL via mxODBC.</p>
<p>mxODBC is available at:</p>
<blockquote>
<div><a class="reference external" href="http://www.egenix.com/">http://www.egenix.com/</a></div></blockquote>
<p>This was tested with mxODBC 3.1.2 and the SQL Server Native
Client connected to MSSQL 2005 and 2008 Express Editions.</p>
<div class="section" id="id2">
<h3>Connecting<a class="headerlink" href="#id2" title="Permalink to this headline">¶</a></h3>
<p>Connection is via DSN:</p>
<div class="highlight-python"><pre>mssql+mxodbc://<username>:<password>@<dsnname></pre>
</div>
</div>
<div class="section" id="execution-modes">
<h3>Execution Modes<a class="headerlink" href="#execution-modes" title="Permalink to this headline">¶</a></h3>
<p>mxODBC features two styles of statement execution, using the
<tt class="docutils literal"><span class="pre">cursor.execute()</span></tt> and <tt class="docutils literal"><span class="pre">cursor.executedirect()</span></tt> methods (the second being
an extension to the DBAPI specification). The former makes use of a particular
API call specific to the SQL Server Native Client ODBC driver known
SQLDescribeParam, while the latter does not.</p>
<p>mxODBC apparently only makes repeated use of a single prepared statement
when SQLDescribeParam is used. The advantage to prepared statement reuse is
one of performance. The disadvantage is that SQLDescribeParam has a limited
set of scenarios in which bind parameters are understood, including that they
cannot be placed within the argument lists of function calls, anywhere outside
the FROM, or even within subqueries within the FROM clause - making the usage
of bind parameters within SELECT statements impossible for all but the most
simplistic statements.</p>
<p>For this reason, the mxODBC dialect uses the “native” mode by default only for
INSERT, UPDATE, and DELETE statements, and uses the escaped string mode for
all other statements.</p>
<p>This behavior can be controlled via
<a class="reference internal" href="../core/expression_api.html#sqlalchemy.sql.expression.Executable.execution_options" title="sqlalchemy.sql.expression.Executable.execution_options"><tt class="xref py py-meth docutils literal"><span class="pre">execution_options()</span></tt></a> using the
<tt class="docutils literal"><span class="pre">native_odbc_execute</span></tt> flag with a value of <tt class="xref docutils literal"><span class="pre">True</span></tt> or <tt class="xref docutils literal"><span class="pre">False</span></tt>, where a
value of <tt class="xref docutils literal"><span class="pre">True</span></tt> will unconditionally use native bind parameters and a value
of <tt class="xref docutils literal"><span class="pre">False</span></tt> will uncondtionally use string-escaped parameters.</p>
</div>
</div>
<div class="section" id="module-sqlalchemy.dialects.mssql.pymssql">
<span id="pymssql"></span><h2>pymssql<a class="headerlink" href="#module-sqlalchemy.dialects.mssql.pymssql" title="Permalink to this headline">¶</a></h2>
<p>Support for the pymssql dialect.</p>
<p>This dialect supports pymssql 1.0 and greater.</p>
<p>pymssql is available at:</p>
<blockquote>
<div><a class="reference external" href="http://pymssql.sourceforge.net/">http://pymssql.sourceforge.net/</a></div></blockquote>
<div class="section" id="id3">
<h3>Connecting<a class="headerlink" href="#id3" title="Permalink to this headline">¶</a></h3>
<p>Sample connect string:</p>
<div class="highlight-python"><pre>mssql+pymssql://<username>:<password>@<freetds_name></pre>
</div>
<p>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.</p>
</div>
<div class="section" id="limitations">
<h3>Limitations<a class="headerlink" href="#limitations" title="Permalink to this headline">¶</a></h3>
<p>pymssql inherits a lot of limitations from FreeTDS, including:</p>
<ul class="simple">
<li>no support for multibyte schema identifiers</li>
<li>poor support for large decimals</li>
<li>poor support for binary fields</li>
<li>poor support for VARCHAR/CHAR fields over 255 characters</li>
</ul>
<p>Please consult the pymssql documentation for further information.</p>
</div>
</div>
<div class="section" id="module-sqlalchemy.dialects.mssql.zxjdbc">
<span id="zxjdbc-notes"></span><h2>zxjdbc Notes<a class="headerlink" href="#module-sqlalchemy.dialects.mssql.zxjdbc" title="Permalink to this headline">¶</a></h2>
<p>Support for the Microsoft SQL Server database via the zxjdbc JDBC
connector.</p>
<div class="section" id="jdbc-driver">
<h3>JDBC Driver<a class="headerlink" href="#jdbc-driver" title="Permalink to this headline">¶</a></h3>
<p>Requires the jTDS driver, available from: <a class="reference external" href="http://jtds.sourceforge.net/">http://jtds.sourceforge.net/</a></p>
</div>
<div class="section" id="id4">
<h3>Connecting<a class="headerlink" href="#id4" title="Permalink to this headline">¶</a></h3>
<p>URLs are of the standard form of
<tt class="docutils literal"><span class="pre">mssql+zxjdbc://user:pass@host:port/dbname[?key=value&key=value...]</span></tt>.</p>
<p>Additional arguments which may be specified either as query string
arguments on the URL, or as keyword arguments to
<a class="reference internal" href="../core/engines.html#sqlalchemy.create_engine" title="sqlalchemy.create_engine"><tt class="xref py py-func docutils literal"><span class="pre">create_engine()</span></tt></a> will be passed as Connection
properties to the underlying JDBC driver.</p>
</div>
</div>
<div class="section" id="module-sqlalchemy.dialects.mssql.adodbapi">
<span id="adodbapi"></span><h2>AdoDBAPI<a class="headerlink" href="#module-sqlalchemy.dialects.mssql.adodbapi" title="Permalink to this headline">¶</a></h2>
<p>The adodbapi dialect is not implemented for 0.6 at this time.</p>
</div>
</div>
</div>
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