Created
March 13, 2012 03:16
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Decision Tree implementation for Django (pesudo code)
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# Based on: http://springfans.com/ieeeSoftware/accChange.pdf | |
class DecisionTable(models.Model): | |
"""Decision Table""" | |
code = models.CharField(unique=True, max_length=8, verbose_name="Unique code for finding a decision table in code") | |
name = models.CharField(blank=True, max_length=100, verbose_name="User friendly name for decision table") | |
def __unicode__(self): | |
return u"Table" | |
class Rule(models.Model): | |
table = models.ForeignKey(DecisionTable) | |
code = models.CharField(unique=True, max_length=8, verbose_name="Unique code for looking up decision tables") | |
name = models.CharField(max_length=128, verbose_name="User friendly description of decision table") | |
priority = PositionField(collection="decision_table") | |
def test(self, facts): | |
for condition in self.condition.all(): | |
if not condition.test(facts): | |
return False | |
return True | |
def __unicode__(self): | |
return u"R%d: %s" % (self.code, self.name) | |
RESPONSE_CHOICES = ( | |
("Yes", True), | |
("No", False), | |
) | |
class Condition(models.Model): | |
"""Boolean condition (e.g. condition must be true / condition must be false).""" | |
rule = models.ForeignKey(Rule) | |
name = models.CharField(blank=False, max_length=128, verbose_name="User friendly description of rule condition") | |
value = models.BooleanField(required=True, default=False, choices=RESPONSE_CHOICES) | |
def test(self, facts): | |
return facts[self.name]==self.value | |
def __unicode__(self): | |
return u"C%d: %s" % (self.code, self.name) | |
class Action(models.Model): | |
"""Data returned by rule""" | |
rule = models.ForeignKey(Rule) | |
code = models.CharField(unique=True, max_length=8, verbose_name="Unique code for identifying actions in code.") | |
name = models.CharField(blank=False, max_length=128, verbose_name="User friendly description of rule action") | |
order = PositionField("rule") | |
def __unicode__(self): | |
return u"A%d: %s" % (self.code, self.name) |
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Merci bcp mon ami ..c'est gentil de votre part je viens de comprendre le principe