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--- wiki2:python:django:models [2019/02/16 20:03]
alfred [Create your own field]
+++ wiki2:python:django:models [2020/05/09 09:25] (actual)
@@ Línea 1: / Línea 1: @@
 ====== Django Models ======
+===== Migrations =====
+<code>
+$ python manage.py makemigrations <app>
+</code>
+Will create migration files for all the apps if the ''app'' was not indicated.
+<code>
+$ python manage.py migrate
+</code>
+Will apply migrations to the configured DB.
 ===== Signals =====
@@ Línea 145: / Línea 156: @@
-==== Create your own field ====
-You need the field and the widget:
-<code python>
+===== How to... =====
-class SelectMultipleChecks(forms.Widget):
+==== Deal with performed queries ====
-    template_name = 'widgets/multiple_checks.html'
+See the current registered queries (with their times):
+<code>
+from django.db import connection
+connection.queries
+</code>
-    def __init__(self, *args, choices=(), defaults=(), **kwargs):
+See a concrete database queries:
-        super().__init__(*args, **kwargs)
+<code>
-        self.choices = choices
+from django.db import connections
+connections['my_db_alias'].queries
-    def get_context(self, name, value, attrs):
-        context = super().get_context(name, value, attrs)
-        context['choices'] = self.choices
-        return context
-class SelectMultipleChecksField(forms.Field):
-    widget = SelectMultipleChecks
-    def __init__(self, *args, choices=(), defaults=(), **kwargs):
-        super().__init__(*args, **kwargs)
-        self.choices = choices
-    def _get_choices(self):
-        return self._choices
-    def _set_choices(self, value):
-        if callable(value):
-            value = CallableChoiceIterator(value)
-        else:
-            value = list(value)
-        self._choices = self.widget.choices = value
-    choices = property(_get_choices, _set_choices)
-    def to_python(self, value):
-        import json
-        values = json.loads(value)
-        i_values = [int(v) for v in values]
-        return [choice for choice in self._choices if choice.pk in i_values]
-    def validate(self, value):
-        assert len(value) > 0
-    def valid_value(self, value):
-        return value
 </code>
-With this we can have the template ''widgets/multiple_checks.html'':
+Delete the query array:
-<code html>
+<code>
-<div style="display: flex; justify-content: space-around;">
+from django.db import reset_queries
-    <input type="hidden" id="{{ widget.attrs.id }}" value="[{{ selected|join:"," }}]">
+reset_queries()
-{% for choice in choices %}
-    <div><input
-            type="checkbox" {% if choice.pk in selected %}checked{% endif %}
-            name="{{widget.attrs.id}}_check"
-            data-id="{{choice.pk}}"
-    > {{ choice }}</div>
-{% endfor %}
-</div>
 </code>
-===== How to... =====
 ==== Get an app model ====
 <code>

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