Added additional documentation to MatematDatabase.
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1 changed files with 10 additions and 2 deletions
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@ -328,10 +328,11 @@ class MatematDatabase(object):
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the statistics table.
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:param user: The user buying a product.
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:param product: The product the user is buying.
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:param count: How many instances of the product the user is buying, defaults to 1.
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:param count: How many units of the product the user is buying, defaults to 1.
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:raises DatabaseConsistencyError: If the user or the product does not exist in the database.
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"""
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with self.db.transaction() as c:
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# Retrieve the consumption entry for the (user, product) pair, if any.
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c.execute('''
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SELECT count
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FROM consumption
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@ -343,6 +344,7 @@ class MatematDatabase(object):
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})
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row = c.fetchone()
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if row is None:
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# If the entry does not exist, create a new one.
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c.execute('''
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INSERT INTO consumption (user_id, product_id, count)
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VALUES (:user_id, :product_id, :count)
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@ -352,6 +354,7 @@ class MatematDatabase(object):
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'count': count
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})
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else:
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# If the entry exists, update the consumption count.
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c.execute('''
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UPDATE consumption
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SET count = count + :count
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@ -361,10 +364,12 @@ class MatematDatabase(object):
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'product_id': product.id,
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'count': count
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})
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# Make sure exactly one consumption row was updated/inserted.
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affected = c.execute('SELECT changes()').fetchone()[0]
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if affected != 1:
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raise DatabaseConsistencyError(
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f'increment_consumption should affect 1 consumption row, but affected {affected}')
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# Compute the cost of the transaction and subtract it from the user's account balance.
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c.execute('''
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UPDATE users
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SET balance = balance - :cost
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@ -372,10 +377,12 @@ class MatematDatabase(object):
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'user_id': user.id,
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'cost': count * product.price_member if user.is_member else count * product.price_non_member
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})
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# Make sure exactly one user row was updated.
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affected = c.execute('SELECT changes()').fetchone()[0]
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if affected != 1:
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raise DatabaseConsistencyError(
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f'increment_consumption should affect 1 users row, but affected {affected}')
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# Subtract the number of purchased units from the product's stock.
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c.execute('''
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UPDATE products
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SET stock = stock - :count
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@ -384,6 +391,7 @@ class MatematDatabase(object):
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'product_id': product.id,
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'count': count
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})
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# Make sure exactly one product row was updated.
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affected = c.execute('SELECT changes()').fetchone()[0]
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if affected != 1:
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raise DatabaseConsistencyError(
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@ -393,7 +401,7 @@ class MatematDatabase(object):
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"""
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Update the stock of a product.
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:param product: The product to restock.
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:param count: Number of instances of the product to add.
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:param count: Number of units of the product to add.
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:raises DatabaseConsistencyError: If the product represented by the object does not exist.
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"""
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with self.db.transaction() as c:
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