Classe do projeto

# -*- coding: utf-8 -*-
from django.db import models
from django.db.models import Q
from datetime import datetime

class Professor(models.Model):
    nome = models.CharField(max_length = 100, unique = True)
    telefone = models.CharField(max_length = 40)
    email = models.EmailField()
    departamento = models.ForeignKey('Departamento')
    cargo = models.ManyToManyField('Cargo')
    curso = models.ManyToManyField('Curso', related_name = 'curso', through = "Matricula")
    data_cadastro_curso = models.DateField(null = True, blank = True)
    def __unicode__(self):
        return self.nome
    class Meta:
        ordering = ['nome']
        verbose_name_plural = u'professores'

class Curso(models.Model):
    nome = models.CharField(max_length = 100)
    data = models.DateTimeField()
    professor = models.CharField(max_length = 100, null = True, blank = True)
    requisitos = models.ManyToManyField('Curso', blank = True, null = True, related_name = 'requisitos_do_curso')
    def __unicode__(self):
        return u'%s - %s' % (self.nome, self.data)

class Matricula(models.Model):
    professor = models.ForeignKey(Professor)
    #curso = models.ForeignKey(Curso, limit_choices_to = (Q(data__gte = datetime.now())))
    curso = models.ForeignKey(Curso)
    concluido = models.BooleanField(blank = True, default = False)
    def __unicode__(self):
        return u" %s no curso %s" % (self.professor.nome, self.curso.nome)
    class Meta:
        db_table = "cadastro_professor_curso"
        verbose_name = u"Matrícula"

class Departamento(models.Model):
    chefe = models.ForeignKey(Professor, related_name = 'chefe_dp')
    nome = models.CharField(max_length = 30)
    obs = models.TextField(blank = True, null = True)
    def __unicode__(self):
        return self.nome

class Cargo(models.Model):
    nome = models.CharField(max_length = 100)
    def __unicode__(self):
        return self.nome