Added database vieww chapter

docs/database_view.rst

@@ -1,2 +1,43 @@
 How to add a database view to Django admin?
 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+You have a database view, created as this::
+
+    create view entities_entity as
+        select id, name from entities_hero
+        union
+        select 10000+id as id, name from entities_villain
+
+
+It has all the names from :code:`Hero` and :code:`Villain`. The id for Villain ae set :code:`10000+id as id`
+because we don't indent to cross 10000 Heroes::
+
+    sqlite> select * from entities_entity;
+    1|Krishna
+    2|Vishnu
+    3|Achilles
+    4|Thor
+    5|Zeus
+    6|Athena
+    7|Apollo
+    10001|Ravana
+    10002|Fenrir
+
+Then you add a :code:`managed=False` model::
+
+    class AllEntity(models.Model):
+        name = models.CharField(max_length=100)
+
+        class Meta:
+            managed = False
+            db_table = "entities_entity"
+
+And add it to admin.::
+
+    @admin.register(AllEntity)
+    class AllEntiryAdmin(admin.ModelAdmin):
+        list_display = ("id", "name")
+
+And your admin looks like this
+
+.. image:: database_view.png

heroes_and_monsters/entities/admin.py

@@ -1,7 +1,7 @@
 from django.contrib import admin
 from django.db.models import Count
 
-from .models import Hero, Villain, Category, Origin, HeroProxy
+from .models import Hero, Villain, Category, Origin, HeroProxy, AllEntity
 
 import csv
 import sys
@@ -196,3 +196,8 @@ def villain_count(self, obj):
 
     hero_count.admin_order_field = '_hero_count'
     villain_count.admin_order_field = '_villain_count'
+
+
+@admin.register(AllEntity)
+class AllEntiryAdmin(admin.ModelAdmin):
+    list_display = ("id", "name")

heroes_and_monsters/entities/models.py

@@ -98,3 +98,10 @@ class Villain(Entity):
     )
     is_unique = models.BooleanField(default=True)
     count = models.PositiveSmallIntegerField(default=1)
+
+class AllEntity(models.Model):
+    name = models.CharField(max_length=100)
+
+    class Meta:
+        managed = False
+        db_table = "entities_entity"