Added sqlite3 database backend -- somewhat tested, but probably not 100% perfect.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@288 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/db/backends/sqlite3.py

@@ -0,0 +1,148 @@
+"""
+SQLite3 backend for django.  Requires pysqlite2 (http://pysqlite.org/).
+"""
+
+from django.core.db import base, typecasts
+from django.core.db.dicthelpers import *
+from pysqlite2 import dbapi2 as Database
+DatabaseError = Database.DatabaseError
+
+# Register adaptors ###########################################################
+
+Database.register_converter("bool", lambda s: str(s) == '1')
+Database.register_converter("time", typecasts.typecast_time)
+Database.register_converter("date", typecasts.typecast_date)
+Database.register_converter("datetime", typecasts.typecast_timestamp)
+
+# Database wrapper ############################################################
+
+class DatabaseWrapper:
+    def __init__(self):
+        self.connection = None
+        self.queries = []
+
+    def cursor(self):
+        from django.conf.settings import DATABASE_NAME, DEBUG
+        if self.connection is None:
+            self.connection = Database.connect(DATABASE_NAME, detect_types=Database.PARSE_DECLTYPES)
+            # register extract and date_trun functions
+            self.connection.create_function("django_extract", 2, _sqlite_extract)
+            self.connection.create_function("django_date_trunc", 2, _sqlite_date_trunc)
+        if DEBUG:
+            return base.CursorDebugWrapper(FormatStylePlaceholderCursor(self.connection), self)
+        return FormatStylePlaceholderCursor(self.connection)
+
+    def commit(self):
+        self.connection.commit()
+
+    def rollback(self):
+        if self.connection:
+            self.connection.rollback()
+
+    def close(self):
+        if self.connection is not None:
+            self.connection.close()
+            self.connection = None
+
+class FormatStylePlaceholderCursor(Database.Cursor):
+    """
+    Django uses "format" style placeholders, but pysqlite2 uses "qmark" style.
+    This fixes it -- but note that if you want to use a literal "%s" in a query,
+    you'll need to use "%%s" (which I belive is true of other wrappers as well).
+    """
+    
+    def execute(self, query, params=[]):
+        query = self.convert_query(query, len(params))
+        return Database.Cursor.execute(self, query, params)
+        
+    def executemany(self, query, params=[]):
+        query = self.convert_query(query, len(params))
+        return Database.Cursor.executemany(self, query, params)
+        
+    def convert_query(self, query, num_params):
+        # XXX this seems too simple to be correct... is this right?
+        return query % tuple("?" * num_params)
+
+# Helper functions ############################################################
+
+def get_last_insert_id(cursor, table_name, pk_name):
+    return cursor.lastrowid
+    
+def get_date_extract_sql(lookup_type, table_name):
+    # lookup_type is 'year', 'month', 'day'
+    # sqlite doesn't support extract, so we fake it with the user-defined 
+    # function _sqlite_extract that's registered in connect(), above.
+    return 'django_extract("%s", %s)' % (lookup_type.lower(), table_name)
+
+def _sqlite_extract(lookup_type, dt):
+    try:
+        dt = typecasts.typecast_timestamp(dt)
+    except (ValueError, TypeError):
+        return None
+    return str(getattr(dt, lookup_type))
+
+def get_date_trunc_sql(lookup_type, field_name):
+    # lookup_type is 'year', 'month', 'day'
+    # sqlite doesn't support DATE_TRUNC, so we fake it as above.
+    return 'django_date_trunc("%s", %s)' % (lookup_type.lower(), field_name)
+
+def _sqlite_date_trunc(lookup_type, dt):
+    try:
+        dt = typecasts.typecast_timestamp(dt)
+    except (ValueError, TypeError):
+        return None
+    if lookup_type == 'year':
+        return "%i-01-01 00:00:00" % dt.year
+    elif lookup_type == 'month':
+        return "%i-%02i-01 00:00:00" % (dt.year, dt.month)
+    elif lookup_type == 'day':
+        return "%i-%02i-%02i 00:00:00" % (dt.year, dt.month, dt.day)
+
+# Operators and fields ########################################################
+        
+OPERATOR_MAPPING = {
+    'exact':        '=',
+    'iexact':       'LIKE',
+    'contains':     'LIKE',
+    'icontains':    'LIKE',
+    'ne':           '!=',
+    'gt':           '>',
+    'gte':          '>=',
+    'lt':           '<',
+    'lte':          '<=',
+    'startswith':   'LIKE',
+    'endswith':     'LIKE',
+    'istartswith':  'LIKE',
+    'iendswith':    'LIKE',
+}
+
+# SQLite doesn't actually support most of these types, but it "does the right 
+# thing" given more verbose field definitions, so leave them as is so that
+# schema inspection is more useful.
+DATA_TYPES = {
+    'AutoField':                    'integer',
+    'BooleanField':                 'bool',
+    'CharField':                    'varchar(%(maxlength)s)',
+    'CommaSeparatedIntegerField':   'varchar(%(maxlength)s)',
+    'DateField':                    'date',
+    'DateTimeField':                'datetime',
+    'EmailField':                   'varchar(75)',
+    'FileField':                    'varchar(100)',
+    'FloatField':                   'numeric(%(max_digits)s, %(decimal_places)s)',
+    'ImageField':                   'varchar(100)',
+    'IntegerField':                 'integer',
+    'IPAddressField':               'char(15)',
+    'ManyToManyField':              None,
+    'NullBooleanField':             'bool',
+    'OneToOneField':                'integer',
+    'PhoneNumberField':             'varchar(20)',
+    'PositiveIntegerField':         'integer unsigned',
+    'PositiveSmallIntegerField':    'smallint unsigned',
+    'SlugField':                    'varchar(50)',
+    'SmallIntegerField':            'smallint',
+    'TextField':                    'text',
+    'TimeField':                    'time',
+    'URLField':                     'varchar(200)',
+    'USStateField':                 'varchar(2)',
+    'XMLField':                     'text',
+}