python - 使用 AND 和 OR 动态连接 Django Q 对象

Question

我希望用户能够通过几个不同的参数(名称、年份等)查询我的数据库，动态添加更多字段，并使用 bool 运算符连接它们；最终结果类似于“年份 = 1900 AND name = chicken AND location = San Francisco”。我认为我做错了什么，因为它没有返回任何东西，即使我只尝试一个我知道匹配某些数据的值的字段(例如，当我从 Django shell 使用 .filter() 时我可以取回对象).任何人都知道我该如何解决它？

相关观点(忽略草率的缩进，我不想经历并修复所有这些，但它在我的实际代码中是正确的):

class BaseSearchFormSet(BaseFormSet):
def clean(self):
    if any(self.errors):
        return self.errors
    queries = []
    valid_courses = ["appetizer","main","dessert"]
    valid_period = re.compile(r'\d\d\d0-\d\d\d5|\d\d\d5-\d\d\d0')
    valid_year = re.compile(r'\d{4}')
    multi_rows = ["year","period","course"]
    for x in xrange(0,self.total_form_count()):
        form = self.forms[x]
        query = form.cleaned_data.get("query")
        row = form.cleaned_data.get("row")
        if query in queries and row not in multi_rows:
            raise forms.ValidationError("You're already searching for %s.")
        queries.append(query)
        if row == "course" and query.lower() not in valid_courses:
            raise forms.ValidationError("%s is not a valid course option."%(form.cleaned_data["query"]))
        if row == "period" and not re.match(valid_period,query):
            raise forms.ValidationError("%s is not a properly formatted period. Valid five-year periods span either the first or second half of a decade. For example: 1910-1915, 1925-1930."%(form.cleaned_data["query"]))
        if row == "year" and not re.match(valid_year,query):
            raise forms.ValidationError("Please enter a four-digit year.")
def search(request):
errors = []
searchFormSet = formset_factory(F.SearchForm, extra=1,formset=BaseSearchFormSet)
if request.GET:
    formset = searchFormSet(request.GET)
    forms = []
    if formset.is_valid():
        for x in xrange(0,formset.total_form_count()):
            form = {}
            form["row"]= formset[x].cleaned_data.get("row",None)
            form["query"] = formset[x].cleaned_data.get("query",None)
            form["bools"] = formset[x].cleaned_data.get("bools",None)
            if form["query"]:
                q = form["query"]
            else:
                errors.append("no query found")
            if form["row"]:
                row = form["row"]
            else:
                errors.append("no row found")
            filter_keys = {"dish_name":Q(dish__name__icontains=q),
                "regex":Q(dish__full_name__regex=r'%s'%(q)),
                "course":Q(dish__classification=q.lower()),
                "year":Q(page__menu_id__year__exact=q),
                "period":Q(page__menu_id__period__exact=q),
                "location":Q(page__menu_id__location__icontains=q),
                "restaurant":Q(page__menu_id__restaurant__icontains=q)}
            forms.append(form)
        final_query=Q()
        def var_reduce(op,slice):
            if op == "and":
                return reduce(lambda x,y: x & y,slice)
            elif op == "or":
                return reduce(lambda x,y: x | y,slice)
        for x in xrange(len(forms)):
            try:
                try:
                    if final_query:
                        slice = [final_query,filter_keys[forms[x]["row"]],filter_keys[forms[x+1]["row"]]]
                    else:
                        slice = [filter_keys[forms[x]["row"]],filter_keys[forms[x+1]["row"]]]
                    final_query = var_reduce(forms[x]["bools"],slice)
                except IndexError:
                    if final_query:
                        slice = [final_query,filter_keys[forms[x]["row"]]]
                    else:
                        slice = [filter_keys[forms[x]["row"]]]
                    final_query = var_reduce(forms[x]["bools"],slice)
                items = MenuItem.objects.filter(final_query)
                return render_to_response("search_results.html",{"items":items,"formset":formset})
            except KeyError as e:
                errors.append(e)    
                formset = searchFormSet(None)
                return render_to_response("search_page.html",{"errors":errors,"formset":formset})
    else:   
        formset = searchFormSet(None)
        return render_to_response("search_page.html",{"errors":errors,"formset":formset})
else:
    formset = searchFormSet(None)
    return render_to_response("search_page.html",{"formset":formset})

模型:

from django.db import models

class MenuItem(models.Model):
def format_price(self):
    return "${0:0<4,.2f}".format(float(self.price))
def __unicode__(self):
    return self.dish
dish=models.OneToOneField('Dish',to_field='mk')
price=models.CharField(max_length=5,blank=True)
page=models.OneToOneField('MenuPage')
mk=models.CharField(max_length=10,unique=True)
formatted_price = property(format_price)
class Menu(models.Model):
def period(self):#adapted from http://stackoverflow.com/questions/2272149/round-to-5or-other-number-in-python
    try:
        p=int(10*round(float(int(self.year))/10))
        if p < self.year:
            return "%s-%s"%(p,p+5)
        else:
            return "%s-%s"%(p-5,p)
    except (ValueError,TypeError):
        return ""
def __unicode__(self):
    if self.restaurant:
        return self.restaurant
    else:
        return self.mk
restaurant=models.TextField(unique=False,blank=True,null=True)
year=models.CharField(max_length=4,unique=False,blank=True,null=True)
location=models.TextField(unique=False,blank=True,null=True)
status=models.CharField(unique=False,max_length=20)
mk=models.CharField(max_length=8,unique=True,primary_key=True)
period=property(period) 
language = models.CharField(unique=False,max_length=30)
#objects=MenuManager()

class MenuPage(models.Model):
mk=models.CharField(max_length=10,unique=True)
menu_id=models.OneToOneField("Menu",to_field='mk')
#objects=MenuPageManager()
class Dish(models.Model):
def __unicode__(self):
    return self.name
full_name = models.TextField()
name=models.CharField(unique=True,max_length=255)
mk=models.CharField(max_length=10,unique=True)
class Classification(models.Model):
def __unicode__(self):
    if self.classification:
        return self.classification
    else:
        return "none"
dish=models.OneToOneField('dish',to_field='name')
classification=models.CharField(unique=False,max_length=9)
mk=models.CharField(max_length=10,primary_key=True)

我的搜索页面的 html:

{% extends "base.html" %}
{% block style %}
<link rel="stylesheet" type="text/css" href="/static/search_style.css" />
{% endblock %}
{% block java %}
<script type="text/javascript" src="/static/searches.js"></script>
{% endblock %}
{% block title %}Search{% endblock %}
{% block head %}Search{% endblock %}
{% block content %}
{% autoescape off %}
<div id="searches">
<form id="search" action="" method="get">
    <table border="0" cellpadding="0" cellspace="0">
        <tbody class="search">
            {% for form in formset.forms %}
            <tr>
                <td class="row">{{ form.row }}</td>
                <td class="query">{{ form.query }}</td>
                <td class="bool">{{ form.bools }}</td>
            </tr>
        {% endfor %}
        </tbody>
    </table>
    {{ formset.management_form }}
    <input type="submit" value="Submit" id="submit">
</form>
</div>
{% if formset.errors or errors %}
<div id="errors">
<h3>The following errors were encountered while trying to submit your search:</h3>
{% for x,y in formset.errors.items %}
<p>{{ x }} : {{ y }}</p>
{% endfor %}
{{ errors }}
</div>
{% endif %}
<div id="notes">
<p>Searching by dish names, locations, and restaurants is case-insensitive.</p>
<p>Searching by course uses  case-insensitive exact matching. Valid courses are Appetizer, Main, and Dessert.</p>
<p>Years should be entered YYYY. Five-year periods span either the first or second half of a decade, and should be entered YYYY-YYYY. Example valid five-year periods are 1900-1905, 1995-2000, etc.</p>
<p>Regular expression search follows MySQL regular expression syntax, as described <a href="http://dev.mysql.com/doc/refman/5.1/en/regexp.html" target="_blank">here</a>.</p>
 </div>

{% endautoescape %}
<br /><br /><br /><br /> <br /><br /><br />
{% endblock %}

{% block footer %}
<div id="warning">
<p>NOTE: This site and the information it contains are still in development. Some information may be missing or inaccurate.</p>
</div>
<div class="credits">
    Created and maintained by <a href="/about#sam">Sam Raker</a> and <a href="/about#rachel">Rachel Rakov</a>
    <br />
    Data graciously provided by <a href="http://menus.nypl.org" target="_blank">What's on the Menu?</a>
</div>
{% endblock %}

Answer 1

抱歉，我原来的帖子超出了您的需要。澄清一下，您需要做的就是:

Q(year__icontains=year_input_variable) | Q(city__icontains=city_input_variable) & Q(name__icontains=name_input_variable)

使用 & 和 |对于或。

我之前发布的内容是，如果一个查询包含多个单词，它会检查是否所有单词都使用运算符匹配。和，或者是否有任何单词使用运算符匹配。 或。