mysql的timestamp类型在django中使用

I'm using django with a legacy mysql db which uses TIMESTAMP columns. Django's inspectdb recognize those fields as int fields. This caused troubles if you want to render its value into a readable date. I googled and found this solution:

http://ianrolfe.livejournal.com/36017.html

from django.db import modelsfrom datetime import datetimefrom time import strftime## Custom field types in here.#class UnixTimestampField(models.DateTimeField):    """UnixTimestampField: creates a DateTimeField that is represented on the    database as a TIMESTAMP field rather than the usual DATETIME field.    """    def __init__(self, null=False, blank=False, **kwargs):        super(UnixTimestampField, self).__init__(**kwargs)        # default for TIMESTAMP is NOT NULL unlike most fields, so we have to        # cheat a little:        self.blank, self.isnull = blank, null        self.null = True # To prevent the framework from shoving in "not null".            def db_type(self):        typ=['TIMESTAMP']        # See above!        if self.isnull:            typ += ['NULL']        if self.auto_created:            typ += ['default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP']        return ' '.join(typ)        def to_python(self, value):        return datetime.from_timestamp(value)        def get_db_prep_value(self, value):        if value==None:            return None        return strftime('%Y%m%d%H%M%S',value.timetuple())

 

It worked, until I started to use lookups on these UnixTimestampField fields(such as __gte, __lte, etc). Django will raise a TypeError if I you do .filter(somefield__lte=datetime.now()).

I made some changes to the original code, and finally the lookups works as well:

 

from datetime import datetimefrom time import strftime,mktime## Custom field types in here.#class UnixTimestampField(models.DateTimeField):    """UnixTimestampField: creates a DateTimeField that is represented on the    database as a TIMESTAMP field rather than the usual DATETIME field.    """    __metaclass__ = models.SubfieldBase    def __init__(self, null=False, blank=False, **kwargs):        super(UnixTimestampField, self).__init__(**kwargs)        # default for TIMESTAMP is NOT NULL unlike most fields, so we have to        # cheat a little:        self.blank, self.isnull = blank, null        self.null = True # To prevent the framework from shoving in "not null".            def db_type(self):        typ=['TIMESTAMP']        # See above!        if self.isnull:            typ += ['NULL']        if self.auto_created:            typ += ['default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP']        return ' '.join(typ)        def to_python(self, value):        return datetime.fromtimestamp(value)    def get_prep_value(self, value):        if value==None:            return None        return mktime(value.timetuple())    def get_db_prep_value(self, value):        if value==None:            return None        return value