def robotsrulesetOfDomain(self, domain):
		'''检查domain是否在数据库中,
			否 --> (False, None)
			是 --> (True, 数据库中存储的robots.txt内容)
		'''
		exist = False
		cur = self.conn.cursor()
		# 是否存在
		cur.execute("SELECT 1 FROM Domains WHERE domain=?", (domain,))
		if cur.fetchone() :
			exist = True
		# 存在的话,结果是什么
		cur.execute("SELECT rules FROM Domains,Rulesets "
			"WHERE domain=? AND Domains.did=Rulesets.did"
			,(domain,) )
		ruleset = cur.fetchone()
		return (exist, ruleset)
def _init_renderers(self):
        """Initializes the cell renderers"""
        # We hide the columns headers
        self.set_headers_visible(False)
        # For the backend icon
        pixbuf_cell = Gtk.CellRendererPixbuf()
        tvcolumn_pixbuf = Gtk.TreeViewColumn('Icon', pixbuf_cell)
        tvcolumn_pixbuf.add_attribute(pixbuf_cell, 'pixbuf', self.COLUMN_ICON)
        self.append_column(tvcolumn_pixbuf)
        # For the backend name
        text_cell = Gtk.CellRendererText()
        tvcolumn_text = Gtk.TreeViewColumn('Name', text_cell)
        tvcolumn_text.add_attribute(text_cell, 'markup', self.COLUMN_TEXT)
        self.append_column(tvcolumn_text)
        text_cell.connect('edited', self.cell_edited_callback)
        text_cell.set_property('editable', True)
        # For the backend tags
        tags_cell = Gtk.CellRendererText()
        tvcolumn_tags = Gtk.TreeViewColumn('Tags', tags_cell)
        tvcolumn_tags.add_attribute(tags_cell, 'markup', self.COLUMN_TAGS)
        self.append_column(tvcolumn_tags)