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 test_ccode_Pow():
    assert ccode(x**3) == "pow(x, 3)"
    assert ccode(x**(y**3)) == "pow(x, pow(y, 3))"
    assert ccode(1/(g(x)*3.5)**(x - y**x)/(x**2 + y)) == \
        "pow(3.5*g(x), -x + pow(y, x))/(pow(x, 2) + y)"
    assert ccode(x**-1.0) == '1.0/x'
    assert ccode(x**Rational(2, 3)) == 'pow(x, 2.0L/3.0L)'
    _cond_cfunc = [(lambda base, exp: exp.is_integer, "dpowi"),
                   (lambda base, exp: not exp.is_integer, "pow")]
    assert ccode(x**3, user_functions={'Pow': _cond_cfunc}) == 'dpowi(x, 3)'
    assert ccode(x**3.2, user_functions={'Pow': _cond_cfunc}) == 'pow(x, 3.2)'