Version Control and Lineage

import pixeltable as pxt

# Version 0: Table created
products = pxt.create_table('demo/products', {
    'name': pxt.String,
    'price': pxt.Float
})

# Version 1: Data inserted
products.insert([
    {'name': 'Widget', 'price': 9.99},
    {'name': 'Gadget', 'price': 24.99}
])

# Version 2: Schema changed
products.add_computed_column(price_with_tax=products.price * 1.08)

# Version 3: Data updated
products.update({'price': 19.99}, where=products.name == 'Widget')

products.history()

versions = products.get_versions()  # List of dictionaries
latest = versions[0]
print(f"Version {latest['version']}: {latest['inserts']} inserts")

# Get the table at version 1 (before computed column)
products_v1 = pxt.get_table('demo/products:1')
products_v1.collect()  # Returns data as it was at version 1

# Compare with current state
products.collect()  # Returns current data

# Oops, wrong update
products.update({'price': 0.00}, where=products.name == 'Widget')

# Undo it
products.revert()  # Removes version N, table is now at version N-1

# Freeze current state before a major data update
baseline = pxt.create_snapshot('demo/products_baseline', products)

# Later: source table changes, but snapshot remains unchanged
products.insert([{'name': 'NewItem', 'price': 99.99}])

products.count()   # 3 rows (updated)
baseline.count()   # 2 rows (frozen)

products.add_computed_column(
    discounted=products.price * 0.9
)
products.add_computed_column(
    discounted_with_tax=products.discounted * 1.08
)

# Pixeltable knows: discounted_with_tax → discounted → price

expensive = pxt.create_view(
    'demo/expensive_products',
    products.where(products.price > 20)
)
# View lineage: expensive_products → products