Add basic ORM example

week11/materials/orm.py

@@ -0,0 +1,70 @@
+import inspect
+
+TYPES = {
+    int: 'INTEGER',
+    str: 'VARCHAR'
+}
+
+
+def map_python_to_sql(py_type):
+    if py_type not in TYPES:
+        return TYPES[str]
+
+    return TYPES[py_type]
+
+
+def varchar():
+    return str
+
+
+def integer():
+    return int
+
+
+def pluralize(string):
+    plural_forms = ['s', 'es']
+
+    for form in plural_forms:
+        if string.endswith(form):
+            return string
+
+    # FIXME: Not a proper english
+    return string + 's'
+
+
+def extract_dict_from_class(cls):
+    members = [m for m in inspect.getmembers(cls)
+               if '__' not in m[0]]
+    attributes = {m[0]: m[1] for m in members}
+    return (cls.__name__, attributes)
+
+
+def class_to_table(name, attributes):
+    create_sql = """
+        CREATE TABLE {name}(
+            id INTEGER PRIMARY KEY AUTO INCRAMENT,
+            {columns}
+        );
+
+    """
+    data = {
+      "name": pluralize(name),
+      "columns": ""
+    }
+
+    columns = []
+    for attr in attributes:
+        value_type = attributes[attr]
+        columns.append("{} {}".format(attr,
+                                      map_python_to_sql(value_type)))
+
+    data['columns'] = ",\n".join(columns)
+    return create_sql.format(**data)
+
+
+class Person:
+    email = varchar()
+    password = varchar()
+    age = integer()
+
+print(class_to_table(*extract_dict_from_class(Person)))