Django 无法连接'；str'；和'；TBMST部门'；物体

上述代码引发了一个错误： 异常值：无法连接“str”和“tbmstdepartment”对象

---

提前感谢它抛出了这个错误，因为

department\u id

是

tbmstdepartment

类的对象；您正试图在查询中连接它

改为这样做：

from django import forms
from django.db.models import Q
from django.core.exceptions import ValidationError
from schdeules.models import tbmsttemplate,tbmstreviewsched,tbtrnrevdepartments,tbtrnrevdesignations,tbmstappraisalsched,tbtrnappraisalreview,tbmstdepartment
class tbmstappraisalschedForm(forms.ModelForm):
    def clean(self):
    """ 
    Override the default clean method to check whether this course has been already inputted.
     """    
        cleaned_data = super(tbmstappraisalschedForm, self).clean()
        #appsched_id = str(self.cleaned_data.get('intAppSchedID'))
        depart_id = self.cleaned_data.get('intDeptID')
        fromdate = str(self.cleaned_data.get('sdtFromDate'))
        todate = str(self.cleaned_data.get('todate'))
        pk=self.instance.pk

        qry = "SELECT intAppSchedID FROM tbMstAppraisalSched WHERE intDeptID ='"+depart_id+"' AND (('"+fromdate+"' BETWEEN  sdtFromDate AND  sdtToDate) OR ('"+todate+"' BETWEEN  sdtFromDate AND sdtToDate))"

        res = tbmstappraisalsched.objects.raw(qry)

        for re in res:
        if(re.intAppSchedID != pk):
            msg = "The slot for selected department and selected dates exists"
            raise ValidationError(msg)
        else:
            return self.cleaned_data
    class Meta:
        model = tbmstappraisalsched

---

使用原始SQL有什么特别的原因吗？我们可以轻松编写复杂的查询。我更不熟悉django sand python。所以我使用原始查询。python的哪个版本？如果它是2的旧分支，请尝试更新版本。您好，它正在工作。但若并没有从查询返回行，那个么它将引发一个类型错误，即；类型为“NoneType”的参数不可iterable。这是另一个单独的问题。你需要问一个新问题。

qry = """
   SELECT
        intAppSchedID
   FROM
        tbMstAppraisalSched
   WHERE
        intDeptID = '{0}'
   AND
        (('{1}' BETWEEN sdtFromDate AND sdtToDate)
   OR
        ('{2}' BETWEEN sdtFromDate and sdtToDate))
"""
res = tbmstappraisalsched.objects.raw(qry.format(depart_id.pk, fromdate, todate))