Bulk insertion for Django models

bulk_insertion.py

class BulkInsertion(object):
    """
    Bulk-insert several model instances using accumulated DB statements.
    
    Usage:
    >>> with BulkInsertion('app_tablename') as inserter:
    ...     inserter.insert(field1=value1, field2=value2)
    
    By default, a DB statement is issued every 1000 inserts.
    
    Note that foreign keys have to be specified by their DB field name, i.e. usually with an _id prefix.
    """
    
    def __init__(self, table, n=1000):
        self.table = table
        self.n = n
    
    def __enter__(self):
        self.objects = []
        return self
    
    def __exit__(self, type, value, tb):
        self.flush()
    
    def insert(self, **object):
        self.objects.append(object)
        if len(self.objects) >= self.n:
            self.flush()
        
    def flush(self):
        if self.objects:
            keys = self.objects[0].keys()
            keys.sort()
            values = []
            for object in self.objects:
                values.extend([object[key] for key in keys])
            cursor = connection.cursor()
            values_placeholder = ','.join(['(%s)' % ','.join(['%s'] * len(keys))] * len(self.objects))
            sql = "INSERT INTO %s (%s) VALUES %s" % (self.table, ",".join(keys), values_placeholder)
            cursor.execute(sql, values)        
        self.objects = []