从另一个模型中检索对象

Question

我遇到这种情况：

class Item (models.Model):
    name = models.Charfield(MaxLenght=15)

class ItemIsHired(models.Model):
    item = models.ForeignKey(Item)
    isHiredNow = models.BooleanField(null=False)

问题是我想要检索现在雇用的所有项目，但是如果我使用ItemIsHired.objects.filter(isHiredNow=True)进行查询，当我需要来自ItemIsHired类时，我会从def valueChartPatterns(dict,path): seen_values = Counter() for data in dict.itervalues(): seen_values += Counter(data.values()) seen_values = seen_values.most_common() seen_values_pct = map(itemgetter(1), tupleCounts2Percents(seen_values)) seen_values_pct = ['{:.2%}'.format(item)for item in seen_values_pct] plt.figure() numberchart = plt.bar(range(len(seen_values)), map(itemgetter(1), seen_values), width=0.9,align='center') plt.xticks(range(len(seen_values)), map(itemgetter(0), seen_values)) plt.title('Values in Pattern Dataset') plt.xlabel('Values in Data') plt.ylabel('Occurrences') plt.tick_params(axis='both', which='major', labelsize=6) plt.tick_params(axis='both', which='minor', labelsize=6) plt.tight_layout() plt.savefig(path) plt.clf() def countryChartPatterns(dict,path): seen_countries = Counter() for data in dict.itervalues(): seen_countries += Counter(data.keys()) seen_countries = seen_countries.most_common() seen_countries_percentage = map(itemgetter(1), tupleCounts2Percents(seen_countries)) seen_countries_percentage = ['{:.2%}'.format(item)for item in seen_countries_percentage] yvals = map(itemgetter(1), seen_countries) xvals = map(itemgetter(0), seen_countries) plt.figure() countrychart = plt.bar(range(len(seen_countries)), yvals, width=0.9,align='center') plt.xticks(range(len(seen_countries)), xvals) plt.title('Countries in Pattern Dataset') plt.xlabel('Countries in Data') plt.ylabel('Occurrences') plt.tick_params(axis='both', which='major', labelsize=6) plt.tick_params(axis='both', which='minor', labelsize=6) plt.tight_layout() plt.savefig(path) plt.clf() 类获取对象与他们相关的Item类。