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 <div class="section" id="module-sqlite3">
<h1>11.13. <tt class="xref docutils literal">sqlite3</tt> &#8212; DB-API 2.0 interface for SQLite databases<a class="headerlink" href="#module-sqlite3" title="Permalink to this headline">¶</a></h1>

New in version 2.5.
SQLite is a C library that provides a lightweight disk-based database that
doesn&#8217;t require a separate server process and allows accessing the database
using a nonstandard variant of the SQL query language. Some applications can use
SQLite for internal data storage. It&#8217;s also possible to prototype an
application using SQLite and then port the code to a larger database such as
PostgreSQL or Oracle.
sqlite3 was written by Gerhard Häring and provides a SQL interface compliant
with the DB-API 2.0 specification described by <a class="reference external" href="http://www.python.org/dev/peps/pep-0249">PEP 249</a>.
To use the module, you must first create a <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a> object that
represents the database. Here the data will be stored in the
<tt class="docutils literal">/tmp/example</tt> file:
<div class="highlight-python"><div class="highlight"><pre>conn = sqlite3.connect(&#39;/tmp/example&#39;)
</pre></div>
</div>
You can also supply the special name <tt class="docutils literal">:memory:</tt> to create a database in RAM.
Once you have a <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a>, you can create a <a title="sqlite3.Cursor" class="reference internal" href="#sqlite3.Cursor"><tt class="xref docutils literal">Cursor</tt></a> object
and call its <a title="sqlite3.Cursor.execute" class="reference internal" href="#sqlite3.Cursor.execute"><tt class="xref docutils literal">execute()</tt></a> method to perform SQL commands:
<div class="highlight-python"><div class="highlight"><pre>c = conn.cursor()

# Create table
c.execute(&#39;&#39;&#39;create table stocks
(date text, trans text, symbol text,
 qty real, price real)&#39;&#39;&#39;)

# Insert a row of data
c.execute(&quot;&quot;&quot;insert into stocks
 values (&#39;2006-01-05&#39;,&#39;BUY&#39;,&#39;RHAT&#39;,100,35.14)&quot;&quot;&quot;)

# Save (commit) the changes
conn.commit()

# We can also close the cursor if we are done with it
c.close()
</pre></div>
</div>
Usually your SQL operations will need to use values from Python variables. You
shouldn&#8217;t assemble your query using Python&#8217;s string operations because doing so
is insecure; it makes your program vulnerable to an SQL injection attack.
Instead, use the DB-API&#8217;s parameter substitution. Put <tt class="docutils literal">?</tt> as a placeholder
wherever you want to use a value, and then provide a tuple of values as the
second argument to the cursor&#8217;s <a title="sqlite3.Cursor.execute" class="reference internal" href="#sqlite3.Cursor.execute"><tt class="xref docutils literal">execute()</tt></a> method. (Other database
modules may use a different placeholder, such as <tt class="docutils literal">%s</tt> or <tt class="docutils literal">:1</tt>.) For
example:
<div class="highlight-python"><div class="highlight"><pre># Never do this -- insecure!
symbol = &#39;IBM&#39;
c.execute(&quot;... where symbol = &#39;%s&#39;&quot; % symbol)

# Do this instead
t = (symbol,)
c.execute(&#39;select * from stocks where symbol=?&#39;, t)

# Larger example
for t in [(&#39;2006-03-28&#39;, &#39;BUY&#39;, &#39;IBM&#39;, 1000, 45.00),
 (&#39;2006-04-05&#39;, &#39;BUY&#39;, &#39;MSOFT&#39;, 1000, 72.00),
 (&#39;2006-04-06&#39;, &#39;SELL&#39;, &#39;IBM&#39;, 500, 53.00),
 ]:
 c.execute(&#39;insert into stocks values (?,?,?,?,?)&#39;, t)
</pre></div>
</div>
To retrieve data after executing a SELECT statement, you can either treat the
cursor as an <a class="reference external" href="../glossary.html#term-iterator">iterator</a>, call the cursor&#8217;s <a title="sqlite3.Cursor.fetchone" class="reference internal" href="#sqlite3.Cursor.fetchone"><tt class="xref docutils literal">fetchone()</tt></a> method to
retrieve a single matching row, or call <a title="sqlite3.Cursor.fetchall" class="reference internal" href="#sqlite3.Cursor.fetchall"><tt class="xref docutils literal">fetchall()</tt></a> to get a list of the
matching rows.
This example uses the iterator form:
<div class="highlight-python"><div class="highlight"><pre>&gt;&gt;&gt; c = conn.cursor()
&gt;&gt;&gt; c.execute(&#39;select * from stocks order by price&#39;)
&gt;&gt;&gt; for row in c:
... print row
...
(u&#39;2006-01-05&#39;, u&#39;BUY&#39;, u&#39;RHAT&#39;, 100, 35.140000000000001)
(u&#39;2006-03-28&#39;, u&#39;BUY&#39;, u&#39;IBM&#39;, 1000, 45.0)
(u&#39;2006-04-06&#39;, u&#39;SELL&#39;, u&#39;IBM&#39;, 500, 53.0)
(u&#39;2006-04-05&#39;, u&#39;BUY&#39;, u&#39;MSOFT&#39;, 1000, 72.0)
&gt;&gt;&gt;
</pre></div>
</div>
<div class="admonition-see-also admonition seealso">
See also
<dl class="last docutils">
<dt><a class="reference external" href="http://code.google.com/p/pysqlite/">http://code.google.com/p/pysqlite/</a></dt>
<dd>The pysqlite web page &#8211; sqlite3 is developed externally under the name
&#8220;pysqlite&#8221;.</dd>
<dt><a class="reference external" href="http://www.sqlite.org">http://www.sqlite.org</a></dt>
<dd>The SQLite web page; the documentation describes the syntax and the
available data types for the supported SQL dialect.</dd>
<dt><a class="reference external" href="http://www.python.org/dev/peps/pep-0249">PEP 249</a> - Database API Specification 2.0</dt>
<dd>PEP written by Marc-André Lemburg.</dd>
</dl>
</div>
<div class="section" id="module-functions-and-constants">
<h2>11.13.1. Module functions and constants<a class="headerlink" href="#module-functions-and-constants" title="Permalink to this headline">¶</a></h2>
<dl class="data">
<dt id="sqlite3.PARSE_DECLTYPES">
<tt class="descclassname">sqlite3.</tt><tt class="descname">PARSE_DECLTYPES</tt><a class="headerlink" href="#sqlite3.PARSE_DECLTYPES" title="Permalink to this definition">¶</a></dt>
<dd>This constant is meant to be used with the detect_types parameter of the
<a title="sqlite3.connect" class="reference internal" href="#sqlite3.connect"><tt class="xref docutils literal">connect()</tt></a> function.
Setting it makes the <tt class="xref docutils literal">sqlite3</tt> module parse the declared type for each
column it returns. It will parse out the first word of the declared type,
i. e. for &#8220;integer primary key&#8221;, it will parse out &#8220;integer&#8221;, or for
&#8220;number(10)&#8221; it will parse out &#8220;number&#8221;. Then for that column, it will look
into the converters dictionary and use the converter function registered for
that type there.
</dd></dl>

<dl class="data">
<dt id="sqlite3.PARSE_COLNAMES">
<tt class="descclassname">sqlite3.</tt><tt class="descname">PARSE_COLNAMES</tt><a class="headerlink" href="#sqlite3.PARSE_COLNAMES" title="Permalink to this definition">¶</a></dt>
<dd>This constant is meant to be used with the detect_types parameter of the
<a title="sqlite3.connect" class="reference internal" href="#sqlite3.connect"><tt class="xref docutils literal">connect()</tt></a> function.
Setting this makes the SQLite interface parse the column name for each column it
returns. It will look for a string formed [mytype] in there, and then decide
that &#8216;mytype&#8217; is the type of the column. It will try to find an entry of
&#8216;mytype&#8217; in the converters dictionary and then use the converter function found
there to return the value. The column name found in <a title="sqlite3.Cursor.description" class="reference internal" href="#sqlite3.Cursor.description"><tt class="xref docutils literal">Cursor.description</tt></a>
is only the first word of the column name, i. e. if you use something like
<tt class="docutils literal">'as &quot;x [datetime]&quot;'</tt> in your SQL, then we will parse out everything until the
first blank for the column name: the column name would simply be &#8220;x&#8221;.
</dd></dl>

<dl class="function">
<dt id="sqlite3.connect">
<tt class="descclassname">sqlite3.</tt><tt class="descname">connect</tt><big>(</big>database[, timeout, isolation_level, detect_types, factory]<big>)</big><a class="headerlink" href="#sqlite3.connect" title="Permalink to this definition">¶</a></dt>
<dd>Opens a connection to the SQLite database file database. You can use
<tt class="docutils literal">&quot;:memory:&quot;</tt> to open a database connection to a database that resides in RAM
instead of on disk.
When a database is accessed by multiple connections, and one of the processes
modifies the database, the SQLite database is locked until that transaction is
committed. The timeout parameter specifies how long the connection should wait
for the lock to go away until raising an exception. The default for the timeout
parameter is 5.0 (five seconds).
For the isolation_level parameter, please see the
<a title="sqlite3.Connection.isolation_level" class="reference internal" href="#sqlite3.Connection.isolation_level"><tt class="xref docutils literal">Connection.isolation_level</tt></a> property of <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a> objects.
SQLite natively supports only the types TEXT, INTEGER, FLOAT, BLOB and NULL. If
you want to use other types you must add support for them yourself. The
detect_types parameter and the using custom converters registered with the
module-level <a title="sqlite3.register_converter" class="reference internal" href="#sqlite3.register_converter"><tt class="xref docutils literal">register_converter()</tt></a> function allow you to easily do that.
detect_types defaults to 0 (i. e. off, no type detection), you can set it to
any combination of <a title="sqlite3.PARSE_DECLTYPES" class="reference internal" href="#sqlite3.PARSE_DECLTYPES"><tt class="xref docutils literal">PARSE_DECLTYPES</tt></a> and <a title="sqlite3.PARSE_COLNAMES" class="reference internal" href="#sqlite3.PARSE_COLNAMES"><tt class="xref docutils literal">PARSE_COLNAMES</tt></a> to turn
type detection on.
By default, the <tt class="xref docutils literal">sqlite3</tt> module uses its <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a> class for the
connect call. You can, however, subclass the <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a> class and make
<a title="sqlite3.connect" class="reference internal" href="#sqlite3.connect"><tt class="xref docutils literal">connect()</tt></a> use your class instead by providing your class for the factory
parameter.
Consult the section <a class="reference internal" href="#sqlite3-types">SQLite and Python types</a> of this manual for details.
The <tt class="xref docutils literal">sqlite3</tt> module internally uses a statement cache to avoid SQL parsing
overhead. If you want to explicitly set the number of statements that are cached
for the connection, you can set the cached_statements parameter. The currently
implemented default is to cache 100 statements.
</dd></dl>

<dl class="function">
<dt id="sqlite3.register_converter">
<tt class="descclassname">sqlite3.</tt><tt class="descname">register_converter</tt><big>(</big>typename, callable<big>)</big><a class="headerlink" href="#sqlite3.register_converter" title="Permalink to this definition">¶</a></dt>
<dd>Registers a callable to convert a bytestring from the database into a custom
Python type. The callable will be invoked for all database values that are of
the type typename. Confer the parameter detect_types of the <a title="sqlite3.connect" class="reference internal" href="#sqlite3.connect"><tt class="xref docutils literal">connect()</tt></a>
function for how the type detection works. Note that the case of typename and
the name of the type in your query must match!</dd></dl>

<dl class="function">
<dt id="sqlite3.register_adapter">
<tt class="descclassname">sqlite3.</tt><tt class="descname">register_adapter</tt><big>(</big>type, callable<big>)</big><a class="headerlink" href="#sqlite3.register_adapter" title="Permalink to this definition">¶</a></dt>
<dd>Registers a callable to convert the custom Python type type into one of
SQLite&#8217;s supported types. The callable callable accepts as single parameter
the Python value, and must return a value of the following types: int, long,
float, str (UTF-8 encoded), unicode or buffer.</dd></dl>

<dl class="function">
<dt id="sqlite3.complete_statement">
<tt class="descclassname">sqlite3.</tt><tt class="descname">complete_statement</tt><big>(</big>sql<big>)</big><a class="headerlink" href="#sqlite3.complete_statement" title="Permalink to this definition">¶</a></dt>
<dd>Returns <a title="True" class="reference external" href="constants.html#True"><tt class="xref xref docutils literal">True</tt></a> if the string sql contains one or more complete SQL
statements terminated by semicolons. It does not verify that the SQL is
syntactically correct, only that there are no unclosed string literals and the
statement is terminated by a semicolon.
This can be used to build a shell for SQLite, as in the following example:
<div class="highlight-python"><div class="highlight"><pre># A minimal SQLite shell for experiments

import sqlite3

buffer = &quot;&quot;

print &quot;Enter your SQL commands to execute in sqlite3.&quot;
print &quot;Enter a blank line to exit.&quot;

while True:
 line = raw_input()
 if line == &quot;&quot;:
 break
 buffer += line
 if sqlite3.complete_statement(buffer):
 try:
 buffer = buffer.strip()
 cur.execute(buffer)

if buffer.lstrip().upper().startswith(&quot;SELECT&quot;):
 print cur.fetchall()
 except sqlite3.Error, e:
 print &quot;An error occurred:&quot;, e.args[0]
 buffer = &quot;&quot;

con.close()
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="sqlite3.enable_callback_tracebacks">
<tt class="descclassname">sqlite3.</tt><tt class="descname">enable_callback_tracebacks</tt><big>(</big>flag<big>)</big><a class="headerlink" href="#sqlite3.enable_callback_tracebacks" title="Permalink to this definition">¶</a></dt>
<dd>By default you will not get any tracebacks in user-defined functions,
aggregates, converters, authorizer callbacks etc. If you want to debug them, you
can call this function with flag as True. Afterwards, you will get tracebacks
from callbacks on <tt class="docutils literal">sys.stderr</tt>. Use <a title="False" class="reference external" href="constants.html#False"><tt class="xref xref docutils literal">False</tt></a> to disable the feature
again.</dd></dl>

</div>
<div class="section" id="connection-objects">
<h2>11.13.2. Connection Objects<a class="headerlink" href="#connection-objects" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="sqlite3.Connection">
class <tt class="descclassname">sqlite3.</tt><tt class="descname">Connection</tt><a class="headerlink" href="#sqlite3.Connection" title="Permalink to this definition">¶</a></dt>
<dd>A SQLite database connection has the following attributes and methods:</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Connection.isolation_level">
<tt class="descclassname">Connection.</tt><tt class="descname">isolation_level</tt><a class="headerlink" href="#sqlite3.Connection.isolation_level" title="Permalink to this definition">¶</a></dt>
<dd>Get or set the current isolation level. <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a> for autocommit mode or
one of &#8220;DEFERRED&#8221;, &#8220;IMMEDIATE&#8221; or &#8220;EXCLUSIVE&#8221;. See section
<a class="reference internal" href="#sqlite3-controlling-transactions">Controlling Transactions</a> for a more detailed explanation.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.cursor">
<tt class="descclassname">Connection.</tt><tt class="descname">cursor</tt><big>(</big>[cursorClass]<big>)</big><a class="headerlink" href="#sqlite3.Connection.cursor" title="Permalink to this definition">¶</a></dt>
<dd>The cursor method accepts a single optional parameter cursorClass. If
supplied, this must be a custom cursor class that extends
<a title="sqlite3.Cursor" class="reference internal" href="#sqlite3.Cursor"><tt class="xref docutils literal">sqlite3.Cursor</tt></a>.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.commit">
<tt class="descclassname">Connection.</tt><tt class="descname">commit</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlite3.Connection.commit" title="Permalink to this definition">¶</a></dt>
<dd>This method commits the current transaction. If you don&#8217;t call this method,
anything you did since the last call to <tt class="docutils literal">commit()</tt> is not visible from from
other database connections. If you wonder why you don&#8217;t see the data you&#8217;ve
written to the database, please check you didn&#8217;t forget to call this method.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.rollback">
<tt class="descclassname">Connection.</tt><tt class="descname">rollback</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlite3.Connection.rollback" title="Permalink to this definition">¶</a></dt>
<dd>This method rolls back any changes to the database since the last call to
<a title="sqlite3.Connection.commit" class="reference internal" href="#sqlite3.Connection.commit"><tt class="xref docutils literal">commit()</tt></a>.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.close">
<tt class="descclassname">Connection.</tt><tt class="descname">close</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlite3.Connection.close" title="Permalink to this definition">¶</a></dt>
<dd>This closes the database connection. Note that this does not automatically
call <a title="sqlite3.Connection.commit" class="reference internal" href="#sqlite3.Connection.commit"><tt class="xref docutils literal">commit()</tt></a>. If you just close your database connection without
calling <a title="sqlite3.Connection.commit" class="reference internal" href="#sqlite3.Connection.commit"><tt class="xref docutils literal">commit()</tt></a> first, your changes will be lost!</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.execute">
<tt class="descclassname">Connection.</tt><tt class="descname">execute</tt><big>(</big>sql[, parameters]<big>)</big><a class="headerlink" href="#sqlite3.Connection.execute" title="Permalink to this definition">¶</a></dt>
<dd>This is a nonstandard shortcut that creates an intermediate cursor object by
calling the cursor method, then calls the cursor&#8217;s
<a title="sqlite3.Cursor.execute" class="reference internal" href="#sqlite3.Cursor.execute"><tt class="xref docutils literal">execute</tt></a> method with the parameters given.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.executemany">
<tt class="descclassname">Connection.</tt><tt class="descname">executemany</tt><big>(</big>sql[, parameters]<big>)</big><a class="headerlink" href="#sqlite3.Connection.executemany" title="Permalink to this definition">¶</a></dt>
<dd>This is a nonstandard shortcut that creates an intermediate cursor object by
calling the cursor method, then calls the cursor&#8217;s
<a title="sqlite3.Cursor.executemany" class="reference internal" href="#sqlite3.Cursor.executemany"><tt class="xref docutils literal">executemany</tt></a> method with the parameters given.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.executescript">
<tt class="descclassname">Connection.</tt><tt class="descname">executescript</tt><big>(</big>sql_script<big>)</big><a class="headerlink" href="#sqlite3.Connection.executescript" title="Permalink to this definition">¶</a></dt>
<dd>This is a nonstandard shortcut that creates an intermediate cursor object by
calling the cursor method, then calls the cursor&#8217;s
<a title="sqlite3.Cursor.executescript" class="reference internal" href="#sqlite3.Cursor.executescript"><tt class="xref docutils literal">executescript</tt></a> method with the parameters
given.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.create_function">
<tt class="descclassname">Connection.</tt><tt class="descname">create_function</tt><big>(</big>name, num_params, func<big>)</big><a class="headerlink" href="#sqlite3.Connection.create_function" title="Permalink to this definition">¶</a></dt>
<dd>Creates a user-defined function that you can later use from within SQL
statements under the function name name. num_params is the number of
parameters the function accepts, and func is a Python callable that is called
as the SQL function.
The function can return any of the types supported by SQLite: unicode, str, int,
long, float, buffer and None.
Example:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3
import md5

def md5sum(t):
 return md5.md5(t).hexdigest()

<dl class="method">
<dt id="sqlite3.Connection.create_aggregate">
<tt class="descclassname">Connection.</tt><tt class="descname">create_aggregate</tt><big>(</big>name, num_params, aggregate_class<big>)</big><a class="headerlink" href="#sqlite3.Connection.create_aggregate" title="Permalink to this definition">¶</a></dt>
<dd>Creates a user-defined aggregate function.
The aggregate class must implement a <tt class="docutils literal">step</tt> method, which accepts the number
of parameters num_params, and a <tt class="docutils literal">finalize</tt> method which will return the
final result of the aggregate.
The <tt class="docutils literal">finalize</tt> method can return any of the types supported by SQLite:
unicode, str, int, long, float, buffer and None.
Example:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

class MySum:
 def __init__(self):
 self.count = 0

def step(self, value):
 self.count += value

def finalize(self):
 return self.count

con = sqlite3.connect(&quot;:memory:&quot;)
con.create_aggregate(&quot;mysum&quot;, 1, MySum)
cur = con.cursor()
cur.execute(&quot;create table test(i)&quot;)
cur.execute(&quot;insert into test(i) values (1)&quot;)
cur.execute(&quot;insert into test(i) values (2)&quot;)
cur.execute(&quot;select mysum(i) from test&quot;)
print cur.fetchone()[0]
</pre></div>
</div>
</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.create_collation">
<tt class="descclassname">Connection.</tt><tt class="descname">create_collation</tt><big>(</big>name, callable<big>)</big><a class="headerlink" href="#sqlite3.Connection.create_collation" title="Permalink to this definition">¶</a></dt>
<dd>Creates a collation with the specified name and callable. The callable will
be passed two string arguments. It should return -1 if the first is ordered
lower than the second, 0 if they are ordered equal and 1 if the first is ordered
higher than the second. Note that this controls sorting (ORDER BY in SQL) so
your comparisons don&#8217;t affect other SQL operations.
Note that the callable will get its parameters as Python bytestrings, which will
normally be encoded in UTF-8.
The following example shows a custom collation that sorts &#8220;the wrong way&#8221;:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

def collate_reverse(string1, string2):
 return -cmp(string1, string2)

cur = con.cursor()
cur.execute(&quot;create table test(x)&quot;)
cur.executemany(&quot;insert into test(x) values (?)&quot;, [(&quot;a&quot;,), (&quot;b&quot;,)])
cur.execute(&quot;select x from test order by x collate reverse&quot;)
for row in cur:
 print row
con.close()
</pre></div>
</div>
To remove a collation, call <tt class="docutils literal">create_collation</tt> with None as callable:
<div class="highlight-python"><div class="highlight"><pre>con.create_collation(&quot;reverse&quot;, None)
</pre></div>
</div>
</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.interrupt">
<tt class="descclassname">Connection.</tt><tt class="descname">interrupt</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlite3.Connection.interrupt" title="Permalink to this definition">¶</a></dt>
<dd>You can call this method from a different thread to abort any queries that might
be executing on the connection. The query will then abort and the caller will
get an exception.</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.set_authorizer">
<tt class="descclassname">Connection.</tt><tt class="descname">set_authorizer</tt><big>(</big>authorizer_callback<big>)</big><a class="headerlink" href="#sqlite3.Connection.set_authorizer" title="Permalink to this definition">¶</a></dt>
<dd>This routine registers a callback. The callback is invoked for each attempt to
access a column of a table in the database. The callback should return
<tt class="xref docutils literal">SQLITE_OK</tt> if access is allowed, <tt class="xref docutils literal">SQLITE_DENY</tt> if the entire SQL
statement should be aborted with an error and <tt class="xref docutils literal">SQLITE_IGNORE</tt> if the
column should be treated as a NULL value. These constants are available in the
<tt class="xref docutils literal">sqlite3</tt> module.
The first argument to the callback signifies what kind of operation is to be
authorized. The second and third argument will be arguments or <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a>
depending on the first argument. The 4th argument is the name of the database
(&#8220;main&#8221;, &#8220;temp&#8221;, etc.) if applicable. The 5th argument is the name of the
inner-most trigger or view that is responsible for the access attempt or
<a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a> if this access attempt is directly from input SQL code.
Please consult the SQLite documentation about the possible values for the first
argument and the meaning of the second and third argument depending on the first
one. All necessary constants are available in the <tt class="xref docutils literal">sqlite3</tt> module.
</dd></dl>

<dl class="method">
<dt id="sqlite3.Connection.set_progress_handler">
<tt class="descclassname">Connection.</tt><tt class="descname">set_progress_handler</tt><big>(</big>handler, n<big>)</big><a class="headerlink" href="#sqlite3.Connection.set_progress_handler" title="Permalink to this definition">¶</a></dt>
<dd>
New in version 2.6.
This routine registers a callback. The callback is invoked for every n
instructions of the SQLite virtual machine. This is useful if you want to
get called from SQLite during long-running operations, for example to update
a GUI.
If you want to clear any previously installed progress handler, call the
method with <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a> for handler.
</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Connection.row_factory">
<tt class="descclassname">Connection.</tt><tt class="descname">row_factory</tt><a class="headerlink" href="#sqlite3.Connection.row_factory" title="Permalink to this definition">¶</a></dt>
<dd>You can change this attribute to a callable that accepts the cursor and the
original row as a tuple and will return the real result row. This way, you can
implement more advanced ways of returning results, such as returning an object
that can also access columns by name.
Example:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

def dict_factory(cursor, row):
 d = {}
 for idx, col in enumerate(cursor.description):
 d[col[0]] = row[idx]
 return d

con = sqlite3.connect(&quot;:memory:&quot;)
con.row_factory = dict_factory
cur = con.cursor()
cur.execute(&quot;select 1 as a&quot;)
print cur.fetchone()[&quot;a&quot;]
</pre></div>
</div>
If returning a tuple doesn&#8217;t suffice and you want name-based access to
columns, you should consider setting <a title="sqlite3.Connection.row_factory" class="reference internal" href="#sqlite3.Connection.row_factory"><tt class="xref docutils literal">row_factory</tt></a> to the
highly-optimized <a title="sqlite3.Row" class="reference internal" href="#sqlite3.Row"><tt class="xref docutils literal">sqlite3.Row</tt></a> type. <a title="sqlite3.Row" class="reference internal" href="#sqlite3.Row"><tt class="xref docutils literal">Row</tt></a> provides both
index-based and case-insensitive name-based access to columns with almost no
memory overhead. It will probably be better than your own custom
dictionary-based approach or even a db_row based solution.
</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Connection.text_factory">
<tt class="descclassname">Connection.</tt><tt class="descname">text_factory</tt><a class="headerlink" href="#sqlite3.Connection.text_factory" title="Permalink to this definition">¶</a></dt>
<dd>Using this attribute you can control what objects are returned for the <tt class="docutils literal">TEXT</tt>
data type. By default, this attribute is set to <a title="unicode" class="reference external" href="functions.html#unicode"><tt class="xref docutils literal">unicode</tt></a> and the
<tt class="xref docutils literal">sqlite3</tt> module will return Unicode objects for <tt class="docutils literal">TEXT</tt>. If you want to
return bytestrings instead, you can set it to <a title="str" class="reference external" href="functions.html#str"><tt class="xref docutils literal">str</tt></a>.
For efficiency reasons, there&#8217;s also a way to return Unicode objects only for
non-ASCII data, and bytestrings otherwise. To activate it, set this attribute to
<tt class="xref docutils literal">sqlite3.OptimizedUnicode</tt>.
You can also set it to any other callable that accepts a single bytestring
parameter and returns the resulting object.
See the following example code for illustration:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

# Create the table
con.execute(&quot;create table person(lastname, firstname)&quot;)

AUSTRIA = u&quot;\xd6sterreich&quot;

# by default, rows are returned as Unicode
cur.execute(&quot;select ?&quot;, (AUSTRIA,))
row = cur.fetchone()
assert row[0] == AUSTRIA

# but we can make sqlite3 always return bytestrings ...
con.text_factory = str
cur.execute(&quot;select ?&quot;, (AUSTRIA,))
row = cur.fetchone()
assert type(row[0]) == str
# the bytestrings will be encoded in UTF-8, unless you stored garbage in the
# database ...
assert row[0] == AUSTRIA.encode(&quot;utf-8&quot;)

# we can also implement a custom text_factory ...
# here we implement one that will ignore Unicode characters that cannot be
# decoded from UTF-8
con.text_factory = lambda x: unicode(x, &quot;utf-8&quot;, &quot;ignore&quot;)
cur.execute(&quot;select ?&quot;, (&quot;this is latin1 and would normally create errors&quot; +
 u&quot;\xe4\xf6\xfc&quot;.encode(&quot;latin1&quot;),))
row = cur.fetchone()
assert type(row[0]) == unicode

# sqlite3 offers a built-in optimized text_factory that will return bytestring
# objects, if the data is in ASCII only, and otherwise return unicode objects
con.text_factory = sqlite3.OptimizedUnicode
cur.execute(&quot;select ?&quot;, (AUSTRIA,))
row = cur.fetchone()
assert type(row[0]) == unicode

cur.execute(&quot;select ?&quot;, (&quot;Germany&quot;,))
row = cur.fetchone()
assert type(row[0]) == str
</pre></div>
</div>
</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Connection.total_changes">
<tt class="descclassname">Connection.</tt><tt class="descname">total_changes</tt><a class="headerlink" href="#sqlite3.Connection.total_changes" title="Permalink to this definition">¶</a></dt>
<dd>Returns the total number of database rows that have been modified, inserted, or
deleted since the database connection was opened.</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Connection.iterdump">
<tt class="descclassname">Connection.</tt><tt class="descname">iterdump</tt><a class="headerlink" href="#sqlite3.Connection.iterdump" title="Permalink to this definition">¶</a></dt>
<dd>Returns an iterator to dump the database in an SQL text format. Useful when
saving an in-memory database for later restoration. This function provides
the same capabilities as the <tt class="docutils literal">.dump</tt> command in the sqlite3
shell.

New in version 2.6.
Example:
<div class="highlight-python"><div class="highlight"><pre># Convert file existing_db.db to SQL dump file dump.sql
import sqlite3, os

</div>
<div class="section" id="cursor-objects">
<h2>11.13.3. Cursor Objects<a class="headerlink" href="#cursor-objects" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="sqlite3.Cursor">
class <tt class="descclassname">sqlite3.</tt><tt class="descname">Cursor</tt><a class="headerlink" href="#sqlite3.Cursor" title="Permalink to this definition">¶</a></dt>
<dd>A SQLite database cursor has the following attributes and methods:</dd></dl>

<dl class="method">
<dt id="sqlite3.Cursor.execute">
<tt class="descclassname">Cursor.</tt><tt class="descname">execute</tt><big>(</big>sql[, parameters]<big>)</big><a class="headerlink" href="#sqlite3.Cursor.execute" title="Permalink to this definition">¶</a></dt>
<dd>Executes an SQL statement. The SQL statement may be parametrized (i. e.
placeholders instead of SQL literals). The <tt class="xref docutils literal">sqlite3</tt> module supports two
kinds of placeholders: question marks (qmark style) and named placeholders
(named style).
This example shows how to use parameters with qmark style:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

cur = con.cursor()

who = &quot;Yeltsin&quot;
age = 72

cur = con.cursor()

who = &quot;Yeltsin&quot;
age = 72

cur.execute(&quot;select name_last, age from people where name_last=:who and age=:age&quot;,
 {&quot;who&quot;: who, &quot;age&quot;: age})
print cur.fetchone()
</pre></div>
</div>
<a title="sqlite3.Cursor.execute" class="reference internal" href="#sqlite3.Cursor.execute"><tt class="xref docutils literal">execute()</tt></a> will only execute a single SQL statement. If you try to execute
more than one statement with it, it will raise a Warning. Use
<a title="sqlite3.Cursor.executescript" class="reference internal" href="#sqlite3.Cursor.executescript"><tt class="xref docutils literal">executescript()</tt></a> if you want to execute multiple SQL statements with one
call.
</dd></dl>

<dl class="method">
<dt id="sqlite3.Cursor.executemany">
<tt class="descclassname">Cursor.</tt><tt class="descname">executemany</tt><big>(</big>sql, seq_of_parameters<big>)</big><a class="headerlink" href="#sqlite3.Cursor.executemany" title="Permalink to this definition">¶</a></dt>
<dd>Executes an SQL command against all parameter sequences or mappings found in
the sequence sql. The <tt class="xref docutils literal">sqlite3</tt> module also allows using an
<a class="reference external" href="../glossary.html#term-iterator">iterator</a> yielding parameters instead of a sequence.
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

class IterChars:
 def __init__(self):
 self.count = ord(&#39;a&#39;)

def __iter__(self):
 return self

def next(self):
 if self.count &gt; ord(&#39;z&#39;):
 raise StopIteration
 self.count += 1
 return (chr(self.count - 1),) # this is a 1-tuple

theIter = IterChars()
cur.executemany(&quot;insert into characters(c) values (?)&quot;, theIter)

cur.execute(&quot;select c from characters&quot;)
print cur.fetchall()
</pre></div>
</div>
Here&#8217;s a shorter example using a <a class="reference external" href="../glossary.html#term-generator">generator</a>:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

def char_generator():
 import string
 for c in string.letters[:26]:
 yield (c,)

cur.executemany(&quot;insert into characters(c) values (?)&quot;, char_generator())

<dl class="method">
<dt id="sqlite3.Cursor.executescript">
<tt class="descclassname">Cursor.</tt><tt class="descname">executescript</tt><big>(</big>sql_script<big>)</big><a class="headerlink" href="#sqlite3.Cursor.executescript" title="Permalink to this definition">¶</a></dt>
<dd>This is a nonstandard convenience method for executing multiple SQL statements
at once. It issues a <tt class="docutils literal">COMMIT</tt> statement first, then executes the SQL script it
gets as a parameter.
sql_script can be a bytestring or a Unicode string.
Example:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

create table book(
 title,
 author,
 published
 );

insert into book(title, author, published)
 values (
 &#39;Dirk Gently&#39;&#39;s Holistic Detective Agency&#39;,
 &#39;Douglas Adams&#39;,
 1987
 );
 &quot;&quot;&quot;)
</pre></div>
</div>
</dd></dl>

<dl class="method">
<dt id="sqlite3.Cursor.fetchone">
<tt class="descclassname">Cursor.</tt><tt class="descname">fetchone</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlite3.Cursor.fetchone" title="Permalink to this definition">¶</a></dt>
<dd>Fetches the next row of a query result set, returning a single sequence,
or <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a> when no more data is available.</dd></dl>

<dl class="method">
<dt id="sqlite3.Cursor.fetchmany">
<tt class="descclassname">Cursor.</tt><tt class="descname">fetchmany</tt><big>(</big>[size=cursor.arraysize]<big>)</big><a class="headerlink" href="#sqlite3.Cursor.fetchmany" title="Permalink to this definition">¶</a></dt>
<dd>Fetches the next set of rows of a query result, returning a list. An empty
list is returned when no more rows are available.
The number of rows to fetch per call is specified by the size parameter.
If it is not given, the cursor&#8217;s arraysize determines the number of rows
to be fetched. The method should try to fetch as many rows as indicated by
the size parameter. If this is not possible due to the specified number of
rows not being available, fewer rows may be returned.
Note there are performance considerations involved with the size parameter.
For optimal performance, it is usually best to use the arraysize attribute.
If the size parameter is used, then it is best for it to retain the same
value from one <a title="sqlite3.Cursor.fetchmany" class="reference internal" href="#sqlite3.Cursor.fetchmany"><tt class="xref docutils literal">fetchmany()</tt></a> call to the next.
</dd></dl>

<dl class="method">
<dt id="sqlite3.Cursor.fetchall">
<tt class="descclassname">Cursor.</tt><tt class="descname">fetchall</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlite3.Cursor.fetchall" title="Permalink to this definition">¶</a></dt>
<dd>Fetches all (remaining) rows of a query result, returning a list. Note that
the cursor&#8217;s arraysize attribute can affect the performance of this operation.
An empty list is returned when no rows are available.</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Cursor.rowcount">
<tt class="descclassname">Cursor.</tt><tt class="descname">rowcount</tt><a class="headerlink" href="#sqlite3.Cursor.rowcount" title="Permalink to this definition">¶</a></dt>
<dd>Although the <a title="sqlite3.Cursor" class="reference internal" href="#sqlite3.Cursor"><tt class="xref docutils literal">Cursor</tt></a> class of the <tt class="xref docutils literal">sqlite3</tt> module implements this
attribute, the database engine&#8217;s own support for the determination of &#8220;rows
affected&#8221;/&#8221;rows selected&#8221; is quirky.
For <tt class="docutils literal">DELETE</tt> statements, SQLite reports <a title="sqlite3.Cursor.rowcount" class="reference internal" href="#sqlite3.Cursor.rowcount"><tt class="xref docutils literal">rowcount</tt></a> as 0 if you make a
<tt class="docutils literal">DELETE FROM table</tt> without any condition.
For <a title="sqlite3.Cursor.executemany" class="reference internal" href="#sqlite3.Cursor.executemany"><tt class="xref docutils literal">executemany()</tt></a> statements, the number of modifications are summed up
into <a title="sqlite3.Cursor.rowcount" class="reference internal" href="#sqlite3.Cursor.rowcount"><tt class="xref docutils literal">rowcount</tt></a>.
As required by the Python DB API Spec, the <a title="sqlite3.Cursor.rowcount" class="reference internal" href="#sqlite3.Cursor.rowcount"><tt class="xref docutils literal">rowcount</tt></a> attribute &#8220;is -1 in
case no <tt class="docutils literal">executeXX()</tt> has been performed on the cursor or the rowcount of the
last operation is not determinable by the interface&#8221;.
This includes <tt class="docutils literal">SELECT</tt> statements because we cannot determine the number of
rows a query produced until all rows were fetched.
</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Cursor.lastrowid">
<tt class="descclassname">Cursor.</tt><tt class="descname">lastrowid</tt><a class="headerlink" href="#sqlite3.Cursor.lastrowid" title="Permalink to this definition">¶</a></dt>
<dd>This read-only attribute provides the rowid of the last modified row. It is
only set if you issued a <tt class="docutils literal">INSERT</tt> statement using the <a title="sqlite3.Cursor.execute" class="reference internal" href="#sqlite3.Cursor.execute"><tt class="xref docutils literal">execute()</tt></a>
method. For operations other than <tt class="docutils literal">INSERT</tt> or when <a title="sqlite3.Cursor.executemany" class="reference internal" href="#sqlite3.Cursor.executemany"><tt class="xref docutils literal">executemany()</tt></a> is
called, <a title="sqlite3.Cursor.lastrowid" class="reference internal" href="#sqlite3.Cursor.lastrowid"><tt class="xref docutils literal">lastrowid</tt></a> is set to <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a>.</dd></dl>

<dl class="attribute">
<dt id="sqlite3.Cursor.description">
<tt class="descclassname">Cursor.</tt><tt class="descname">description</tt><a class="headerlink" href="#sqlite3.Cursor.description" title="Permalink to this definition">¶</a></dt>
<dd>This read-only attribute provides the column names of the last query. To
remain compatible with the Python DB API, it returns a 7-tuple for each
column where the last six items of each tuple are <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a>.
It is set for <tt class="docutils literal">SELECT</tt> statements without any matching rows as well.
</dd></dl>

</div>
<div class="section" id="row-objects">
<h2>11.13.4. Row Objects<a class="headerlink" href="#row-objects" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="sqlite3.Row">
class <tt class="descclassname">sqlite3.</tt><tt class="descname">Row</tt><a class="headerlink" href="#sqlite3.Row" title="Permalink to this definition">¶</a></dt>
<dd>A <a title="sqlite3.Row" class="reference internal" href="#sqlite3.Row"><tt class="xref docutils literal">Row</tt></a> instance serves as a highly optimized
<a title="sqlite3.Connection.row_factory" class="reference internal" href="#sqlite3.Connection.row_factory"><tt class="xref docutils literal">row_factory</tt></a> for <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a> objects.
It tries to mimic a tuple in most of its features.
It supports mapping access by column name and index, iteration,
representation, equality testing and <a title="len" class="reference external" href="functions.html#len"><tt class="xref docutils literal">len()</tt></a>.
If two <a title="sqlite3.Row" class="reference internal" href="#sqlite3.Row"><tt class="xref docutils literal">Row</tt></a> objects have exactly the same columns and their
members are equal, they compare equal.

Changed in version 2.6: Added iteration and equality (hashability).
<dl class="method">
<dt id="sqlite3.Row.keys">
<tt class="descname">keys</tt><big>(</big><big>)</big><a class="headerlink" href="#sqlite3.Row.keys" title="Permalink to this definition">¶</a></dt>
<dd>This method returns a tuple of column names. Immediately after a query,
it is the first member of each tuple in <a title="sqlite3.Cursor.description" class="reference internal" href="#sqlite3.Cursor.description"><tt class="xref docutils literal">Cursor.description</tt></a>.

New in version 2.6.
</dd></dl>

</dd></dl>

Let&#8217;s assume we initialize a table as in the example given above:
<div class="highlight-python"><div class="highlight"><pre>conn = sqlite3.connect(&quot;:memory:&quot;)
c = conn.cursor()
c.execute(&#39;&#39;&#39;create table stocks
(date text, trans text, symbol text,
 qty real, price real)&#39;&#39;&#39;)
c.execute(&quot;&quot;&quot;insert into stocks
 values (&#39;2006-01-05&#39;,&#39;BUY&#39;,&#39;RHAT&#39;,100,35.14)&quot;&quot;&quot;)
conn.commit()
c.close()
</pre></div>
</div>
Now we plug <a title="sqlite3.Row" class="reference internal" href="#sqlite3.Row"><tt class="xref docutils literal">Row</tt></a> in:
<div class="highlight-python"><div class="highlight"><pre>&gt;&gt;&gt; conn.row_factory = sqlite3.Row
&gt;&gt;&gt; c = conn.cursor()
&gt;&gt;&gt; c.execute(&#39;select * from stocks&#39;)
&lt;sqlite3.Cursor object at 0x7f4e7dd8fa80&gt;
&gt;&gt;&gt; r = c.fetchone()
&gt;&gt;&gt; type(r)
&lt;type &#39;sqlite3.Row&#39;&gt;
&gt;&gt;&gt; r
(u&#39;2006-01-05&#39;, u&#39;BUY&#39;, u&#39;RHAT&#39;, 100.0, 35.140000000000001)
&gt;&gt;&gt; len(r)
5
&gt;&gt;&gt; r[2]
u&#39;RHAT&#39;
&gt;&gt;&gt; r.keys()
[&#39;date&#39;, &#39;trans&#39;, &#39;symbol&#39;, &#39;qty&#39;, &#39;price&#39;]
&gt;&gt;&gt; r[&#39;qty&#39;]
100.0
&gt;&gt;&gt; for member in r: print member
...
2006-01-05
BUY
RHAT
100.0
35.14
</pre></div>
</div>
</div>
<div class="section" id="sqlite-and-python-types">
<h2>11.13.5. SQLite and Python types<a class="headerlink" href="#sqlite-and-python-types" title="Permalink to this headline">¶</a></h2>
<div class="section" id="introduction">
<h3>11.13.5.1. Introduction<a class="headerlink" href="#introduction" title="Permalink to this headline">¶</a></h3>
SQLite natively supports the following types: <tt class="docutils literal">NULL</tt>, <tt class="docutils literal">INTEGER</tt>,
<tt class="docutils literal">REAL</tt>, <tt class="docutils literal">TEXT</tt>, <tt class="docutils literal">BLOB</tt>.
The following Python types can thus be sent to SQLite without any problem:
<table border="1" class="docutils">
<colgroup>
<col width="69%" />
<col width="31%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Python type</th>
<th class="head">SQLite type</th>
</tr>
</thead>
<tbody valign="top">
<tr><td><a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a></td>
<td><tt class="docutils literal">NULL</tt></td>
</tr>
<tr><td><a title="int" class="reference external" href="functions.html#int"><tt class="xref docutils literal">int</tt></a></td>
<td><tt class="docutils literal">INTEGER</tt></td>
</tr>
<tr><td><a title="long" class="reference external" href="functions.html#long"><tt class="xref docutils literal">long</tt></a></td>
<td><tt class="docutils literal">INTEGER</tt></td>
</tr>
<tr><td><a title="float" class="reference external" href="functions.html#float"><tt class="xref docutils literal">float</tt></a></td>
<td><tt class="docutils literal">REAL</tt></td>
</tr>
<tr><td><a title="str" class="reference external" href="functions.html#str"><tt class="xref docutils literal">str</tt></a> (UTF8-encoded)</td>
<td><tt class="docutils literal">TEXT</tt></td>
</tr>
<tr><td><a title="unicode" class="reference external" href="functions.html#unicode"><tt class="xref docutils literal">unicode</tt></a></td>
<td><tt class="docutils literal">TEXT</tt></td>
</tr>
<tr><td><a title="buffer" class="reference external" href="functions.html#buffer"><tt class="xref docutils literal">buffer</tt></a></td>
<td><tt class="docutils literal">BLOB</tt></td>
</tr>
</tbody>
</table>
This is how SQLite types are converted to Python types by default:
<table border="1" class="docutils">
<colgroup>
<col width="22%" />
<col width="78%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">SQLite type</th>
<th class="head">Python type</th>
</tr>
</thead>
<tbody valign="top">
<tr><td><tt class="docutils literal">NULL</tt></td>
<td><a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal">None</tt></a></td>
</tr>
<tr><td><tt class="docutils literal">INTEGER</tt></td>
<td><a title="int" class="reference external" href="functions.html#int"><tt class="xref docutils literal">int</tt></a> or <a title="long" class="reference external" href="functions.html#long"><tt class="xref docutils literal">long</tt></a>,
depending on size</td>
</tr>
<tr><td><tt class="docutils literal">REAL</tt></td>
<td><a title="float" class="reference external" href="functions.html#float"><tt class="xref docutils literal">float</tt></a></td>
</tr>
<tr><td><tt class="docutils literal">TEXT</tt></td>
<td>depends on <a title="sqlite3.Connection.text_factory" class="reference internal" href="#sqlite3.Connection.text_factory"><tt class="xref docutils literal">text_factory</tt></a>,
<a title="unicode" class="reference external" href="functions.html#unicode"><tt class="xref docutils literal">unicode</tt></a> by default</td>
</tr>
<tr><td><tt class="docutils literal">BLOB</tt></td>
<td><a title="buffer" class="reference external" href="functions.html#buffer"><tt class="xref docutils literal">buffer</tt></a></td>
</tr>
</tbody>
</table>
The type system of the <tt class="xref docutils literal">sqlite3</tt> module is extensible in two ways: you can
store additional Python types in a SQLite database via object adaptation, and
you can let the <tt class="xref docutils literal">sqlite3</tt> module convert SQLite types to different Python
types via converters.
</div>
<div class="section" id="using-adapters-to-store-additional-python-types-in-sqlite-databases">
<h3>11.13.5.2. Using adapters to store additional Python types in SQLite databases<a class="headerlink" href="#using-adapters-to-store-additional-python-types-in-sqlite-databases" title="Permalink to this headline">¶</a></h3>
As described before, SQLite supports only a limited set of types natively. To
use other Python types with SQLite, you must adapt them to one of the
sqlite3 module&#8217;s supported types for SQLite: one of NoneType, int, long, float,
str, unicode, buffer.
The <tt class="xref docutils literal">sqlite3</tt> module uses Python object adaptation, as described in
<a class="reference external" href="http://www.python.org/dev/peps/pep-0246">PEP 246</a> for this. The protocol to use is <tt class="xref docutils literal">PrepareProtocol</tt>.
There are two ways to enable the <tt class="xref docutils literal">sqlite3</tt> module to adapt a custom Python
type to one of the supported ones.
<div class="section" id="letting-your-object-adapt-itself">
<h4>11.13.5.2.1. Letting your object adapt itself<a class="headerlink" href="#letting-your-object-adapt-itself" title="Permalink to this headline">¶</a></h4>
This is a good approach if you write the class yourself. Let&#8217;s suppose you have
a class like this:
<div class="highlight-python"><div class="highlight"><pre>class Point(object):
 def __init__(self, x, y):
 self.x, self.y = x, y
</pre></div>
</div>
Now you want to store the point in a single SQLite column. First you&#8217;ll have to
choose one of the supported types first to be used for representing the point.
Let&#8217;s just use str and separate the coordinates using a semicolon. Then you need
to give your class a method <tt class="docutils literal">__conform__(self, protocol)</tt> which must return
the converted value. The parameter protocol will be <tt class="xref docutils literal">PrepareProtocol</tt>.
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

class Point(object):
 def __init__(self, x, y):
 self.x, self.y = x, y

def __conform__(self, protocol):
 if protocol is sqlite3.PrepareProtocol:
 return &quot;%f;%f&quot; % (self.x, self.y)

p = Point(4.0, -3.2)
cur.execute(&quot;select ?&quot;, (p,))
print cur.fetchone()[0]
</pre></div>
</div>
</div>
<div class="section" id="registering-an-adapter-callable">
<h4>11.13.5.2.2. Registering an adapter callable<a class="headerlink" href="#registering-an-adapter-callable" title="Permalink to this headline">¶</a></h4>
The other possibility is to create a function that converts the type to the
string representation and register the function with <a title="sqlite3.register_adapter" class="reference internal" href="#sqlite3.register_adapter"><tt class="xref docutils literal">register_adapter()</tt></a>.
<div class="admonition note">
Note
The type/class to adapt must be a <a class="reference external" href="../glossary.html#term-new-style-class">new-style class</a>, i. e. it must have
<a title="object" class="reference external" href="functions.html#object"><tt class="xref docutils literal">object</tt></a> as one of its bases.
</div>
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

def adapt_point(point):
 return &quot;%f;%f&quot; % (point.x, point.y)

sqlite3.register_adapter(Point, adapt_point)

p = Point(4.0, -3.2)
cur.execute(&quot;select ?&quot;, (p,))
print cur.fetchone()[0]
</pre></div>
</div>
The <tt class="xref docutils literal">sqlite3</tt> module has two default adapters for Python&#8217;s built-in
<a title="datetime.date" class="reference external" href="datetime.html#datetime.date"><tt class="xref docutils literal">datetime.date</tt></a> and <a title="datetime.datetime" class="reference external" href="datetime.html#datetime.datetime"><tt class="xref docutils literal">datetime.datetime</tt></a> types. Now let&#8217;s suppose
we want to store <a title="datetime.datetime" class="reference external" href="datetime.html#datetime.datetime"><tt class="xref docutils literal">datetime.datetime</tt></a> objects not in ISO representation,
but as a Unix timestamp.
<div class="highlight-python"><div class="highlight"><pre>import sqlite3
import datetime, time

def adapt_datetime(ts):
 return time.mktime(ts.timetuple())

sqlite3.register_adapter(datetime.datetime, adapt_datetime)

now = datetime.datetime.now()
cur.execute(&quot;select ?&quot;, (now,))
print cur.fetchone()[0]
</pre></div>
</div>
</div>
</div>
<div class="section" id="converting-sqlite-values-to-custom-python-types">
<h3>11.13.5.3. Converting SQLite values to custom Python types<a class="headerlink" href="#converting-sqlite-values-to-custom-python-types" title="Permalink to this headline">¶</a></h3>
Writing an adapter lets you send custom Python types to SQLite. But to make it
really useful we need to make the Python to SQLite to Python roundtrip work.
Enter converters.
Let&#8217;s go back to the <tt class="xref docutils literal">Point</tt> class. We stored the x and y coordinates
separated via semicolons as strings in SQLite.
First, we&#8217;ll define a converter function that accepts the string as a parameter
and constructs a <tt class="xref docutils literal">Point</tt> object from it.
<div class="admonition note">
Note
Converter functions always get called with a string, no matter under which
data type you sent the value to SQLite.
</div>
<div class="highlight-python"><div class="highlight"><pre>def convert_point(s):
 x, y = map(float, s.split(&quot;;&quot;))
 return Point(x, y)
</pre></div>
</div>
Now you need to make the <tt class="xref docutils literal">sqlite3</tt> module know that what you select from
the database is actually a point. There are two ways of doing this:
<ul class="simple">
<li>Implicitly via the declared type</li>
<li>Explicitly via the column name</li>
</ul>
Both ways are described in section <a class="reference internal" href="#sqlite3-module-contents">Module functions and constants</a>, in the entries
for the constants <a title="sqlite3.PARSE_DECLTYPES" class="reference internal" href="#sqlite3.PARSE_DECLTYPES"><tt class="xref docutils literal">PARSE_DECLTYPES</tt></a> and <a title="sqlite3.PARSE_COLNAMES" class="reference internal" href="#sqlite3.PARSE_COLNAMES"><tt class="xref docutils literal">PARSE_COLNAMES</tt></a>.
The following example illustrates both approaches.
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

def __repr__(self):
 return &quot;(%f;%f)&quot; % (self.x, self.y)

def convert_point(s):
 x, y = map(float, s.split(&quot;;&quot;))
 return Point(x, y)

# Register the adapter
sqlite3.register_adapter(Point, adapt_point)

# Register the converter
sqlite3.register_converter(&quot;point&quot;, convert_point)

#########################
# 1) Using declared types
con = sqlite3.connect(&quot;:memory:&quot;, detect_types=sqlite3.PARSE_DECLTYPES)
cur = con.cursor()
cur.execute(&quot;create table test(p point)&quot;)

#######################
# 1) Using column names
con = sqlite3.connect(&quot;:memory:&quot;, detect_types=sqlite3.PARSE_COLNAMES)
cur = con.cursor()
cur.execute(&quot;create table test(p)&quot;)

cur.execute(&quot;insert into test(p) values (?)&quot;, (p,))
cur.execute(&#39;select p as &quot;p [point]&quot; from test&#39;)
print &quot;with column names:&quot;, cur.fetchone()[0]
cur.close()
con.close()
</pre></div>
</div>
</div>
<div class="section" id="default-adapters-and-converters">
<h3>11.13.5.4. Default adapters and converters<a class="headerlink" href="#default-adapters-and-converters" title="Permalink to this headline">¶</a></h3>
There are default adapters for the date and datetime types in the datetime
module. They will be sent as ISO dates/ISO timestamps to SQLite.
The default converters are registered under the name &#8220;date&#8221; for
<a title="datetime.date" class="reference external" href="datetime.html#datetime.date"><tt class="xref docutils literal">datetime.date</tt></a> and under the name &#8220;timestamp&#8221; for
<a title="datetime.datetime" class="reference external" href="datetime.html#datetime.datetime"><tt class="xref docutils literal">datetime.datetime</tt></a>.
This way, you can use date/timestamps from Python without any additional
fiddling in most cases. The format of the adapters is also compatible with the
experimental SQLite date/time functions.
The following example demonstrates this.
<div class="highlight-python"><div class="highlight"><pre>import sqlite3
import datetime

today = datetime.date.today()
now = datetime.datetime.now()

cur.execute(&quot;insert into test(d, ts) values (?, ?)&quot;, (today, now))
cur.execute(&quot;select d, ts from test&quot;)
row = cur.fetchone()
print today, &quot;=&gt;&quot;, row[0], type(row[0])
print now, &quot;=&gt;&quot;, row[1], type(row[1])

cur.execute(&#39;select current_date as &quot;d [date]&quot;, current_timestamp as &quot;ts [timestamp]&quot;&#39;)
row = cur.fetchone()
print &quot;current_date&quot;, row[0], type(row[0])
print &quot;current_timestamp&quot;, row[1], type(row[1])
</pre></div>
</div>
</div>
</div>
<div class="section" id="controlling-transactions">
<h2>11.13.6. Controlling Transactions<a class="headerlink" href="#controlling-transactions" title="Permalink to this headline">¶</a></h2>
By default, the <tt class="xref docutils literal">sqlite3</tt> module opens transactions implicitly before a
Data Modification Language (DML) statement (i.e.
<tt class="docutils literal">INSERT</tt>/<tt class="docutils literal">UPDATE</tt>/<tt class="docutils literal">DELETE</tt>/<tt class="docutils literal">REPLACE</tt>), and commits transactions
implicitly before a non-DML, non-query statement (i. e.
anything other than <tt class="docutils literal">SELECT</tt> or the aforementioned).
So if you are within a transaction and issue a command like <tt class="docutils literal">CREATE TABLE
...</tt>, <tt class="docutils literal">VACUUM</tt>, <tt class="docutils literal">PRAGMA</tt>, the <tt class="xref docutils literal">sqlite3</tt> module will commit implicitly
before executing that command. There are two reasons for doing that. The first
is that some of these commands don&#8217;t work within transactions. The other reason
is that sqlite3 needs to keep track of the transaction state (if a transaction
is active or not).
You can control which kind of <tt class="docutils literal">BEGIN</tt> statements sqlite3 implicitly executes
(or none at all) via the isolation_level parameter to the <a title="sqlite3.connect" class="reference internal" href="#sqlite3.connect"><tt class="xref docutils literal">connect()</tt></a>
call, or via the <tt class="xref docutils literal">isolation_level</tt> property of connections.
If you want autocommit mode, then set <tt class="xref docutils literal">isolation_level</tt> to None.
Otherwise leave it at its default, which will result in a plain &#8220;BEGIN&#8221;
statement, or set it to one of SQLite&#8217;s supported isolation levels: &#8220;DEFERRED&#8221;,
&#8220;IMMEDIATE&#8221; or &#8220;EXCLUSIVE&#8221;.
</div>
<div class="section" id="using-sqlite3-efficiently">
<h2>11.13.7. Using <tt class="xref docutils literal">sqlite3</tt> efficiently<a class="headerlink" href="#using-sqlite3-efficiently" title="Permalink to this headline">¶</a></h2>
<div class="section" id="using-shortcut-methods">
<h3>11.13.7.1. Using shortcut methods<a class="headerlink" href="#using-shortcut-methods" title="Permalink to this headline">¶</a></h3>
Using the nonstandard <tt class="xref docutils literal">execute()</tt>, <tt class="xref docutils literal">executemany()</tt> and
<tt class="xref docutils literal">executescript()</tt> methods of the <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a> object, your code can
be written more concisely because you don&#8217;t have to create the (often
superfluous) <a title="sqlite3.Cursor" class="reference internal" href="#sqlite3.Cursor"><tt class="xref docutils literal">Cursor</tt></a> objects explicitly. Instead, the <a title="sqlite3.Cursor" class="reference internal" href="#sqlite3.Cursor"><tt class="xref docutils literal">Cursor</tt></a>
objects are created implicitly and these shortcut methods return the cursor
objects. This way, you can execute a <tt class="docutils literal">SELECT</tt> statement and iterate over it
directly using only a single call on the <a title="sqlite3.Connection" class="reference internal" href="#sqlite3.Connection"><tt class="xref docutils literal">Connection</tt></a> object.
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

persons = [
 (&quot;Hugo&quot;, &quot;Boss&quot;),
 (&quot;Calvin&quot;, &quot;Klein&quot;)
 ]

# Create the table
con.execute(&quot;create table person(firstname, lastname)&quot;)

# Fill the table
con.executemany(&quot;insert into person(firstname, lastname) values (?, ?)&quot;, persons)

# Print the table contents
for row in con.execute(&quot;select firstname, lastname from person&quot;):
 print row

# Using a dummy WHERE clause to not let SQLite take the shortcut table deletes.
print &quot;I just deleted&quot;, con.execute(&quot;delete from person where 1=1&quot;).rowcount, &quot;rows&quot;
</pre></div>
</div>
</div>
<div class="section" id="accessing-columns-by-name-instead-of-by-index">
<h3>11.13.7.2. Accessing columns by name instead of by index<a class="headerlink" href="#accessing-columns-by-name-instead-of-by-index" title="Permalink to this headline">¶</a></h3>
One useful feature of the <tt class="xref docutils literal">sqlite3</tt> module is the built-in
<a title="sqlite3.Row" class="reference internal" href="#sqlite3.Row"><tt class="xref docutils literal">sqlite3.Row</tt></a> class designed to be used as a row factory.
Rows wrapped with this class can be accessed both by index (like tuples) and
case-insensitively by name:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

cur = con.cursor()
cur.execute(&quot;select name_last, age from people&quot;)
for row in cur:
 assert row[0] == row[&quot;name_last&quot;]
 assert row[&quot;name_last&quot;] == row[&quot;nAmE_lAsT&quot;]
 assert row[1] == row[&quot;age&quot;]
 assert row[1] == row[&quot;AgE&quot;]
</pre></div>
</div>
</div>
<div class="section" id="using-the-connection-as-a-context-manager">
<h3>11.13.7.3. Using the connection as a context manager<a class="headerlink" href="#using-the-connection-as-a-context-manager" title="Permalink to this headline">¶</a></h3>

New in version 2.6.
Connection objects can be used as context managers
that automatically commit or rollback transactions. In the event of an
exception, the transaction is rolled back; otherwise, the transaction is
committed:
<div class="highlight-python"><div class="highlight"><pre>import sqlite3

# Successful, con.commit() is called automatically afterwards
with con:
 con.execute(&quot;insert into person(firstname) values (?)&quot;, (&quot;Joe&quot;,))

# con.rollback() is called after the with block finishes with an exception, the
# exception is still raised and must be catched
try:
 with con:
 con.execute(&quot;insert into person(firstname) values (?)&quot;, (&quot;Joe&quot;,))
except sqlite3.IntegrityError:
 print &quot;couldn&#39;t add Joe twice&quot;
</pre></div>
</div>
</div>
</div>
</div>

</div>
 </div>
 </div>
 <div class="sphinxsidebar">
 <div class="sphinxsidebarwrapper">
 <h3><a href="../contents.html">Table Of Contents</a></h3>
 <ul>
<li><a class="reference external" href="#">11.13. <tt class="docutils literal">sqlite3</tt> &#8212; DB-API 2.0 interface for SQLite databases</a><ul>
<li><a class="reference external" href="#module-functions-and-constants">11.13.1. Module functions and constants</a></li>
<li><a class="reference external" href="#connection-objects">11.13.2. Connection Objects</a></li>
<li><a class="reference external" href="#cursor-objects">11.13.3. Cursor Objects</a></li>
<li><a class="reference external" href="#row-objects">11.13.4. Row Objects</a></li>
<li><a class="reference external" href="#sqlite-and-python-types">11.13.5. SQLite and Python types</a><ul>
<li><a class="reference external" href="#introduction">11.13.5.1. Introduction</a></li>
<li><a class="reference external" href="#using-adapters-to-store-additional-python-types-in-sqlite-databases">11.13.5.2. Using adapters to store additional Python types in SQLite databases</a><ul>
<li><a class="reference external" href="#letting-your-object-adapt-itself">11.13.5.2.1. Letting your object adapt itself</a></li>
<li><a class="reference external" href="#registering-an-adapter-callable">11.13.5.2.2. Registering an adapter callable</a></li>
</ul>
</li>
<li><a class="reference external" href="#converting-sqlite-values-to-custom-python-types">11.13.5.3. Converting SQLite values to custom Python types</a></li>
<li><a class="reference external" href="#default-adapters-and-converters">11.13.5.4. Default adapters and converters</a></li>
</ul>
</li>
<li><a class="reference external" href="#controlling-transactions">11.13.6. Controlling Transactions</a></li>
<li><a class="reference external" href="#using-sqlite3-efficiently">11.13.7. Using <tt class="docutils literal">sqlite3</tt> efficiently</a><ul>
<li><a class="reference external" href="#using-shortcut-methods">11.13.7.1. Using shortcut methods</a></li>
<li><a class="reference external" href="#accessing-columns-by-name-instead-of-by-index">11.13.7.2. Accessing columns by name instead of by index</a></li>
<li><a class="reference external" href="#using-the-connection-as-a-context-manager">11.13.7.3. Using the connection as a context manager</a></li>
</ul>
</li>
</ul>
</li>
</ul>

<h4>Previous topic</h4>
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 title="previous chapter">11.12. <tt class="docutils literal docutils literal docutils literal">dumbdbm</tt> &#8212; Portable DBM implementation</a>
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