document django book

doc/source/django.rst

@@ -1,2 +1,130 @@
 Working with django database
 ================================================================================
+
+.. testcode::
+   :hide:
+
+    >>> class Attributable:
+    ...     def __init__(self, adict):
+    ...         self.mydict = adict
+    ...         
+    ...     def __getattr__(self, field):
+    ...         return self.mydict[field]
+    ... 
+    >>> class Objects:
+    ...     def __init__(self):
+    ...         self.objs = None
+    ...         
+    ...     def bulk_create(self, objs, batch_size):
+    ...         self.objs = objs
+    ...         self.batch_size = batch_size
+    ... 
+    ...     def all(self):
+    ...         return [Attributable(o) for o in self.objs]
+    ... 
+    >>> class Field:
+    ...     def __init__(self, name):
+    ...         self.attname = name
+    ... 
+    >>> class Meta:
+    ...     def __init__(self):
+    ...         self.model_name = "test"
+    ...         self.concrete_fields = []
+    ... 
+    ...     def update(self, data):
+    ...         for f in data:
+    ...             self.concrete_fields.append(Field(f))
+
+This section shows the way to to write and read from django database. Becuase it
+is "heavy"" to include a django site here to show you. A mocked django model is
+used here to demonstate it::
+
+    >>> class FakeDjangoModel:
+    ...     def __init__(self):
+    ...         self.objects = Objects()
+    ...         self._meta = Meta()
+    ... 
+    ...     def __call__(self, **keywords):
+    ...         return keywords
+
+Write data to a django model
+--------------------------------------------------------------------------------
+
+Let's suppose we have a django model:
+
+    >>> from pyexcel_io import save_data, DB_DJANGO
+    >>> model = FakeDjangoModel()
+
+Suppose you have these data::
+
+    >>> data  = [
+    ...     ["X", "Y", "Z"],
+    ...     [1, 2, 3],
+    ...     [4, 5, 6]
+    ... ]
+    >>> save_data(DB_DJANGO, data[1:], models={"csv": [model, data[0], None, None]})
+    >>> model.objects.objs
+    [{'Y': 2, 'X': 1, 'Z': 3}, {'Y': 5, 'X': 4, 'Z': 6}]
+
+Read data from a django model
+--------------------------------------------------------------------------------
+
+.. testcode::
+   :hide:
+
+   >>> model._meta.update(["X", "Y", "Z"])
+
+Continue from previous example, you can read this back::
+
+   >>> from pyexcel_io import get_data
+   >>> data = get_data(DB_DJANGO, models=[model])
+   >>> data
+   [['X', 'Y', 'Z'], [1, 2, 3], [4, 5, 6]]
+
+Write data into multiple models
+--------------------------------------------------------------------------------
+
+Suppose you have the following data to be stored in the database:
+
+    >>> data = {
+    ...     "Sheet1": [['X', 'Y', 'Z'], [1, 4, 7], [2, 5, 8], [3, 6, 9]],
+    ...     "Sheet2": [['A', 'B', 'C'], [1, 4, 7], [2, 5, 8], [3, 6, 9]]
+    ... }
+
+And want to save them to two django models:
+
+    >>> model1 = FakeDjangoModel()
+    >>> model2 = FakeDjangoModel()
+
+In order to store a dictionary data structure, you need to do some transformation::
+
+    >>> to_store = {
+    ...    "Sheet1": data['Sheet1'][1:],
+    ...    "Sheet2": data['Sheet2'][1:]
+    ... }
+    >>> models = {
+    ...    "Sheet1": [model1, data['Sheet1'][0], None, None],
+    ...    "Sheet2": [model2, data['Sheet2'][0], None, None]
+    ... }
+    >>> save_data(DB_DJANGO, to_store, models=models)
+    >>> model1.objects.objs
+    [{'Y': 4, 'X': 1, 'Z': 7}, {'Y': 5, 'X': 2, 'Z': 8}, {'Y': 6, 'X': 3, 'Z': 9}]
+    >>> model2.objects.objs
+    [{'A': 1, 'C': 7, 'B': 4}, {'A': 2, 'C': 8, 'B': 5}, {'A': 3, 'C': 9, 'B': 6}]
+
+.. testcode:
+   :hide:
+
+   >>> model1._meta.model_name = "Sheet1"
+   >>> model2._meta.model_name = "Sheet2"
+   >>> model1._meta.update(["X", "Y", "Z"])
+   >>> model2._meta.update(["A", "B", "C"])
+   
+Read content from multiple tables
+--------------------------------------------------------------------------------
+
+Here's what you need to do:
+
+    >>> data = get_data(DB_DJANGO, models=[model1, model2])
+    >>> data
+    OrderedDict([('Sheet1', [['X', 'Y', 'Z'], [1, 4, 7], [2, 5, 8], [3, 6, 9]]), ('Sheet2', [['A', 'B', 'C'], [1, 4, 7], [2, 5, 8], [3, 6, 9]])])