:file:`/tmp/example` file::
import sqlite3
- conn = sqlite3.connect('/tmp/example')
+ conn = sqlite3.connect('example.db')
You can also supply the special name ``:memory:`` to create a database in RAM.
c = conn.cursor()
# Create table
- c.execute('''create table stocks
- (date text, trans text, symbol text,
- qty real, price real)''')
+ c.execute('''CREATE TABLE stocks
+ (date text, trans text, symbol text, qty real, price real)''')
# Insert a row of data
- c.execute("""insert into stocks
- values ('2006-01-05','BUY','RHAT',100,35.14)""")
+ c.execute("INSERT INTO stocks VALUES ('2006-01-05','BUY','RHAT',100,35.14)")
# Save (commit) the changes
conn.commit()
# We can also close the cursor if we are done with it
c.close()
-Usually your SQL operations will need to use values from Python variables. You
-shouldn't assemble your query using Python's string operations because doing so
-is insecure; it makes your program vulnerable to an SQL injection attack.
-
The data you've saved is persistent and is available in subsequent sessions::
import sqlite3
- conn = sqlite3.connect('/tmp/example')
+ conn = sqlite3.connect('example.db')
c = conn.cursor()
+Usually your SQL operations will need to use values from Python variables. You
+shouldn't assemble your query using Python's string operations because doing so
+is insecure; it makes your program vulnerable to an SQL injection attack
+(see http://xkcd.com/327/ for humorous example of what can go wrong).
+
Instead, use the DB-API's parameter substitution. Put ``?`` as a placeholder
wherever you want to use a value, and then provide a tuple of values as the
second argument to the cursor's :meth:`~Cursor.execute` method. (Other database
example::
# Never do this -- insecure!
- symbol = 'IBM'
- c.execute("select * from stocks where symbol = '%s'" % symbol)
+ symbol = 'RHAT'
+ c.execute("SELECT * FROM stocks WHERE symbol = '%s'" % symbol)
# Do this instead
t = (symbol,)
- c.execute('select * from stocks where symbol=?', t)
+ c.execute('SELECT * FROM stocks WHERE symbol=?', t)
+ print c.fetchone()
- # Larger example
- for t in [('2006-03-28', 'BUY', 'IBM', 1000, 45.00),
- ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00),
- ('2006-04-06', 'SELL', 'IBM', 500, 53.00),
- ]:
- c.execute('insert into stocks values (?,?,?,?,?)', t)
+ # Larger example that inserts many records at a time
+ purchases = [('2006-03-28', 'BUY', 'IBM', 1000, 45.00),
+ ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00),
+ ('2006-04-06', 'SELL', 'IBM', 500, 53.00),
+ ]
+ c.executemany('INSERT INTO stocks VALUES (?,?,?,?,?)', purchases)
To retrieve data after executing a SELECT statement, you can either treat the
cursor as an :term:`iterator`, call the cursor's :meth:`~Cursor.fetchone` method to
This example uses the iterator form::
- >>> c = conn.cursor()
- >>> c.execute('select * from stocks order by price')
- >>> for row in c:
- ... print row
- ...
+ >>> for row in c.execute('SELECT * FROM stocks ORDER BY price'):
+ print row
+
(u'2006-01-05', u'BUY', u'RHAT', 100, 35.14)
(u'2006-03-28', u'BUY', u'IBM', 1000, 45.0)
(u'2006-04-06', u'SELL', u'IBM', 500, 53.0)
(u'2006-04-05', u'BUY', u'MSFT', 1000, 72.0)
- >>>
.. seealso::
The SQLite web page; the documentation describes the syntax and the
available data types for the supported SQL dialect.
+ http://www.w3schools.com/sql/
+ Tutorial, reference and examples for learning SQL syntax.
+
:pep:`249` - Database API Specification 2.0
PEP written by Marc-André Lemburg.