Database schema change. Implement ProductCategory.

* The user can now create product categories with the 'category add' command.
* The user can now add products to categories with the
  'product add --category INT' command.

cli.py

@@ -5,7 +5,8 @@ from datetime import datetime
 
 from pos.config import Config
 from pos.logging import init_logging, get_logger
-from pos.database import Database, User, Event, Product, Transaction
+from pos.database import Database, User, Event, ProductCategory, Product,\
+                         Transaction
 
 config = Config()
 conf_db = config.core['DATABASE']
@@ -30,6 +31,14 @@ def cli():
     pass
 
 
+@cli.command('initdb')
+def initdb():
+    with db.get_session() as session:
+        categories = session.query(ProductCategory).count()
+        if not categories:
+            session.add(ProductCategory(name='Default'))
+
+
 @cli.group('user')
 def user():
     pass
@@ -218,15 +227,60 @@ def event_set(event_uid, name, start, end):
         print(tabulate_events([event]))
 
 
+@cli.group('category')
+def category():
+    pass
+
+
+@category.command('add')
+@click.option('-s', '--sort', type=click.INT)
+@click.argument('name')
+def category_add(name, sort):
+    category = ProductCategory(name=name)
+
+    if sort:
+        category.sort = sort
+
+    with db.get_session() as session:
+        session.add(category)
+    print("Category successfully added.")
+
+
+def tabulate_categories(categories):
+    tab = [["UID", "Name", "Sort", "Created at"]]
+    for c in categories:
+        tab.append([c.uid, c.name, c.sort, c.created_at])
+    return tabulate(tab, headers='firstrow')
+
+
+@category.command('list')
+@click.option('-s', '--sort', is_flag=True)
+def category_list(sort):
+    with db.get_session() as session:
+        categories = session.query(ProductCategory)
+
+    if sort:
+        categories = categories.order_by(ProductCategory.sort.asc())
+
+    categories = categories.all()
+
+    if categories:
+        print(tabulate_categories(categories))
+    else:
+        print("No categories found.")
+
+
 @cli.group('product')
 def product():
     pass
 
 
 def tabulate_products(products):
-    tab = [["UID", "Name", "Price", "Sort", "Enabled", "Created at"]]
+    tab = [["UID", "Name", "Price", "Sort", "Category",
+            "Enabled", "Created at"]]
     for p in products:
-        tab.append([p.uid, p.name, p.price, p.sort, p.is_active, p.created_at])
+        tab.append([p.uid, p.name, p.price, p.sort, p.category.name,
+                    p.is_active, p.created_at])
     return tabulate(tab, headers='firstrow')
 
 
@@ -234,12 +288,18 @@ def tabulate_products(products):
 @click.argument('name')
 @click.argument('price')
 @click.option('-s', '--sort', type=click.INT)
-def product_add(name, price, sort):
+@click.option('-c', '--category', type=click.INT)
+def product_add(name, price, sort, category):
     product = Product(name=name, price=price)
 
     if sort:
         product.sort = sort
 
+    if category:
+        product.category_uid = category
+    else:
+        product.category_uid = 1
+
     with db.get_session() as session:
         session.add(product)
     print("Product successfully added.")
@@ -266,8 +326,9 @@ def product_list(sort):
 @click.option('-n', '--name')
 @click.option('-p', '--price', type=click.INT)
 @click.option('-s', '--sort', type=click.INT)
+@click.option('-c', '--category', type=click.INT)
 @click.argument('product_uid')
-def product_set(product_uid, name, price, sort):
+def product_set(product_uid, name, price, sort, category):
     with db.get_session() as session:
         product = session.query(Product).get(product_uid)
 
@@ -284,7 +345,10 @@ def product_set(product_uid, name, price, sort):
     if sort:
         product.sort = sort
 
-    if any([name, price, sort]):
+    if category:
+        product.category_uid = category
+
+    if any([name, price, sort, category]):
         with db.get_session() as session:
             session.add(product)
         print("Event successfully edited.")

pos/database.py

@@ -113,15 +113,29 @@ class Event(Base):
     transactions = relationship('Transaction', lazy='joined')
 
 
+class ProductCategory(Base):
+    __tablename__ = 'product_categories'
+    uid = Column(Integer, primary_key=True)
+    name = Column(String, nullable=False)
+    sort = Column(Integer, nullable=False, server_default='0')
+    created_at = Column(DateTime, nullable=False, default=datetime.now)
+
+    products = relationship('Product', lazy='joined')
+
+
 class Product(Base):
     __tablename__ = 'products'
     uid = Column(Integer, primary_key=True)
     name = Column(String, nullable=False)
     price = Column(Integer, nullable=False)
     sort = Column(Integer, nullable=False, server_default='0')
+    category_uid = Column(Integer, ForeignKey('product_categories.uid'),
+                          nullable=False)
     is_active = Column(Boolean, nullable=False, server_default='1')
     created_at = Column(DateTime, nullable=False, default=datetime.now)
 
+    category = relationship('ProductCategory', lazy='joined')
+
 
 order_entry_association = Table(
     'order_entry_associations', Base.metadata,