'Create the basic database structure.'

def _create(self):

    try:
        self.execute(u'SELECT    *    FROM    nick_ids;')
        self.execute(u'SELECT    *    FROM    nicknames;')
        self.execute(u'SELECT    *    FROM    nick_values;')
        self.execute(u'SELECT    *    FROM    channel_values;')
    except:
        pass
    else:
        return
    self.execute(u'CREATE    TABLE    nick_ids    (nick_id    INTEGER    PRIMARY    KEY    AUTOINCREMENT)')
    self.execute(u'CREATE    TABLE    nicknames    (nick_id    INTEGER    REFERENCES    nick_ids,    slug    STRING    PRIMARY    KEY,    canonical    string)')
    self.execute(u'CREATE    TABLE    nick_values    (nick_id    INTEGER    REFERENCES    nick_ids(nick_id),    key    STRING,    value    STRING,    PRIMARY    KEY    (nick_id,    key))')
    self.execute(u'CREATE    TABLE    channel_values    (channel    STRING,    key    STRING,    value    STRING,    PRIMARY    KEY    (channel,    key))')
