訪問一個特定的項目在我的數據庫的聲明

Question

我有一個有點奇怪的情況。我正在使用通過物業管理軟件訪問的只讀數據庫。它們允許用戶在那裏定義軟件中的字段。但是，它們不會顯示爲數據庫中的特定字段。該數據庫有兩個與它們相關的表格propuserdefined和propuserdefinedvalues。 propuserdefined包含有關該字段（id，名稱，描述）的所有信息propuserdiefinedvalues包含與該屬性相關聯的值。它有propid，userdefinedid和value。我的問題是，我需要訪問propuserdefinedvalues的值，其中propid等於propid在我的財產屬性聲明和userdefinedid等於49.我將如何做到這一點？它是否帶有模板標籤？

在此先感謝您的幫助。
Brandon

這是我的模型。

class Propuserdefined(models.Model): 
    userdefinedid = models.IntegerField(primary_key=True) 
    name = models.CharField(max_length=50L, blank=True) 
    type = models.IntegerField() 
    userid = models.IntegerField(null=True, blank=True) 
    updated = models.DateTimeField(null=True, blank=True) 
    datecreated = models.DateTimeField(null=True, blank=True) 
    combolist = models.TextField(blank=True) 
    class Meta: 
     db_table = 'propuserdefined' 

class Propuserdefinedvalues(models.Model): 
    userdefinedid = models.IntegerField() 
    propid = models.IntegerField() 
    value = models.TextField(blank=True) 
    userid = models.IntegerField(null=True, blank=True) 
    updated = models.DateTimeField(null=True, blank=True) 
    datecreated = models.DateTimeField(null=True, blank=True) 
    class Meta: 
     db_table = 'propuserdefinedvalues' 

class Property(models.Model): 
    propid = models.IntegerField(primary_key=True) 
    name = models.CharField(max_length=35L, blank=True) 
    shortname = models.CharField(max_length=6L, blank=True) 
    street1 = models.CharField(max_length=50L, blank=True) 
    street2 = models.CharField(max_length=50L, blank=True) 
    city = models.CharField(max_length=50L, blank=True) 
    state = models.CharField(max_length=2L, blank=True) 
    zip = models.CharField(max_length=50L, blank=True) 
    phone = models.CharField(max_length=21L, blank=True) 
    fax = models.CharField(max_length=50L, blank=True) 
    email = models.CharField(max_length=255L, blank=True) 
    manager = models.CharField(max_length=25L, blank=True) 
    billname1 = models.CharField(max_length=35L, blank=True) 
    billname2 = models.CharField(max_length=35L, blank=True) 
    billstreet1 = models.CharField(max_length=50L, blank=True) 
    billstreet2 = models.CharField(max_length=50L, blank=True) 
    billcity = models.CharField(max_length=50L, blank=True) 
    billstate = models.CharField(max_length=2L, blank=True) 
    billzip = models.CharField(max_length=50L, blank=True) 
    proptaxid = models.CharField(max_length=35L, blank=True) 
    rentchargetype = models.CharField(max_length=20L, blank=True) 
    lastpostdate = models.DateField(null=True, blank=True) 
    lastweeklypostdate = models.DateField(null=True, blank=True) 
    comments = models.CharField(max_length=25L, blank=True) 
    enablespeciallatecharge = models.IntegerField(null=True, blank=True) 
    fixedlatecharge = models.IntegerField(null=True, blank=True) 
    fixedlateamount = models.FloatField(null=True, blank=True) 
    fixedlaterentonly = models.IntegerField(null=True, blank=True) 
    percentlate = models.IntegerField(null=True, blank=True) 
    percentlateamount = models.FloatField(null=True, blank=True) 
    percentlatefullcharge = models.IntegerField(null=True, blank=True) 
    percentlaterentonly = models.IntegerField(null=True, blank=True) 
    perdaylate = models.IntegerField(null=True, blank=True) 
    perdaylateamount = models.FloatField(null=True, blank=True) 
    perdaylategrace = models.IntegerField(null=True, blank=True) 
    perdaylategracenum = models.IntegerField(null=True, blank=True) 
    perdatelatelimitamount = models.FloatField() 
    perdaylategracenonretro = models.IntegerField() 
    perdaylategraceexclweekends = models.IntegerField() 
    perdaylategraceexclholidays = models.IntegerField() 
    datecreated = models.DateTimeField(null=True, blank=True) 
    updated = models.DateTimeField(null=True, blank=True) 
    userid = models.IntegerField(null=True, blank=True) 
    logofile = models.CharField(max_length=255L, blank=True) 
    merchantid = models.CharField(max_length=255L, blank=True) 
    epaybankid = models.IntegerField() 
    epaylimit = models.FloatField() 
    epayenabled = models.IntegerField() 
    achconveniencefeeenabled = models.IntegerField() 
    ccconveniencefeeenabled = models.IntegerField() 
    rwaachconvenciencefeeenabled = models.IntegerField() 
    rwaccconveniencefeeenabled = models.IntegerField() 
    epayislimited = models.IntegerField() 
    epayusedefaults = models.IntegerField() 
    achconveniencefee = models.FloatField(null=True, blank=True) 
    ccconveniencefee = models.FloatField(null=True, blank=True) 
    rwaachconveniencefee = models.FloatField(null=True, blank=True) 
    rwaccconveniencefee = models.FloatField(null=True, blank=True) 
    epaychargetype = models.IntegerField() 
    epayamounttype = models.IntegerField() 
    epaysetamount = models.FloatField() 
    epaycustlimit = models.FloatField() 
    sqft = models.IntegerField() 
    lateminbalance = models.FloatField(null=True, blank=True) 
    defaultbank = models.IntegerField() 
    postday = models.IntegerField(null=True, blank=True) 
    active = models.IntegerField(null=True, blank=True) 
    iscommercial = models.IntegerField(null=True, blank=True) 
    assignedissueuserid = models.IntegerField(null=True, blank=True) 
    altname = Propuserdefinedvalues.objects.filter(userdefinedid=49) 
    class Meta: 
     db_table = 'property' 

Answer 1

這聽起來像你正試圖在Django模板中做到這一點。你應該改用Python代碼，因爲Django模板並不是爲此設計的。

該表的Django模型也不會提供訪問這些屬性的最佳界面。相反，你應該在它們之上創建一些功能。或者，您可以編寫在兩個表中進行連接的原始SQL。

Answer 2

使用你的模型，因爲它們是（有沒有ForeignKeys定義，所以你不能使用ORM跟隨關係），就可以得到這樣的細節（如果我理解正確你的問題）：

property = Property.objects.get(name='my_property_name') # or however you get the property 
prop_user_defined_values = Propuserdefinedvalues.objects.filter(propid=property.id, userdefinedid=49) 

但是，如果你改變了你的模型的順序，這可能短路，並且你的一些字段中鍵入ForiegnKey：

class Property(models.Model): 
    # ... rest truncated ... 

class Propuserdefined(models.Model): 
    # ... rest truncated ... 

class Propuserdefinedvalues(models.Model): 
    property = models.ForeignKey(Property, db_column='propid') 
    userdefined = models.ForeignKey(Propuserdefined, db_column='userdefinedid') 
    # ... rest truncated ... 

這將讓你做這樣的事情：

Propuserdefinedvalues.objects.filter(userdefined__name='my_name', property__name='my_property') 
# or: 
my_property = Property.objects.get(name='my_property') 
Propuserdefinedvalues.objects.filter(userdefined__userdefinedid=49, property=my_property) 

我建議你在這裏閱讀關於Django的模型：https://docs.djangoproject.com/en/1.5/topics/db/models/ - 只要你知道關係，即使你有預先存在的表格，它們也很容易得到正確的結果。

（免責聲明：未經測試的代碼可能是bug;）你使用Django，根據標籤