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Generate UUIDs for automatic row identification.

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Problem

You need unique identifiers for rows in your data pipeline. Maybe you’re building an API that returns specific records, tracking processing status across systems, or joining data from multiple sources.

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Solution

What’s in this recipe:
  • Create tables with auto-generated UUID primary keys
  • Add UUID columns to existing tables
  • Generate UUIDs with uuid7()
You use uuid7() to generate UUIDs for each row. Define it in the schema with {'column_name': uuid7()} syntax, or add it to existing tables with add_computed_column().

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Setup

%pip install -qU pixeltable

import pixeltable as pxt
from pixeltable.functions.uuid import uuid7

# Create a fresh directory
pxt.drop_dir('uuid_demo', force=True)
pxt.create_dir('uuid_demo')

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Create a table with a UUID primary key

Use uuid7() in your schema to create a column that auto-generates UUIDs: 
# Create table with auto-generated UUID primary key
products = pxt.create_table(
    'uuid_demo/products',
    {
        'id': uuid7(),  # Auto-generates UUID for each row
        'name': pxt.String,
        'price': pxt.Float,
    },
    primary_key=['id'],
)

Created table ‘products’.
# Insert data - no need to provide 'id', it's auto-generated
products.insert(
    [
        {'name': 'Laptop', 'price': 999.99},
        {'name': 'Mouse', 'price': 29.99},
        {'name': 'Keyboard', 'price': 79.99},
    ]
)

Inserted 3 rows with 0 errors in 0.02 s (191.21 rows/s)
3 rows inserted.
# View the data - each row has a unique UUID
products.collect()

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Add a UUID column to an existing table

You can add a UUID column to a table that already exists using add_computed_column(): 
# Create a table without a UUID column
orders = pxt.create_table(
    'uuid_demo/orders', {'customer': pxt.String, 'amount': pxt.Float}
)

Created table ‘orders’.
# Insert some data
orders.insert(
    [
        {'customer': 'Alice', 'amount': 150.00},
        {'customer': 'Bob', 'amount': 75.50},
    ]
)

Inserted 2 rows with 0 errors in 0.01 s (310.49 rows/s)
2 rows inserted.
# Add a UUID column to existing table
orders.add_computed_column(order_id=uuid7())

Added 2 column values with 0 errors in 0.02 s (98.14 rows/s)
2 rows updated.
# View orders with their UUID column
orders.collect()

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Explanation

Two ways to add UUIDs:
Both use uuid7() which generates UUIDv7 (time-based) identifiers:
  • 128-bit values
  • Formatted as 32 hex digits with hyphens: 018e65c5-35e5-7c5d-8f37-f1c5b9c8a7b2
  • Time-ordered for better database performance
  • Virtually guaranteed unique (collision probability is negligible)

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See also

Last modified on May 1, 2026