sqllocks-spindle 1.2.0

Multi-domain, schema-aware synthetic data generator for Microsoft Fabric

Spindle by SQLLocks

"Synthea is to MITRE as Spindle is to SQLLocks"

Spindle is a multi-domain, schema-aware synthetic data generator for Microsoft Fabric. It generates statistically realistic, relationally correct datasets — think normalized 3NF schemas with proper FK integrity, Pareto order distributions, seasonal temporal patterns, and real US addresses with lat/lng coordinates ready for Power BI maps.

pip install sqllocks-spindle

---

Quick Start

from sqllocks_spindle import Spindle, RetailDomain

spindle = Spindle()
result = spindle.generate(
    domain=RetailDomain(),
    scale="small",
    seed=42
)

print(result)
# GenerationResult(9 tables, 21,300 total rows, 0.3s)

# Access any table as a pandas DataFrame
customers = result["customer"]
orders    = result["order"]
addresses = result["address"]

# Check referential integrity
errors = result.verify_integrity()
assert errors == []

# Print a generation summary
print(result.summary())

---

Domains

Spindle ships 12 production-ready domains — each with calibrated distribution profiles, referential integrity enforcement, and 20+ passing tests:

Domain	Tables	Description
Retail	9	Customers, products, orders, returns — 3NF normalized
Healthcare	9	Patients, encounters, diagnoses, claims — 3NF normalized
Financial	10	Branches, accounts, transactions, loans, fraud detection
Supply Chain	10	Warehouses, suppliers, POs, inventory, shipments
IoT	8	Devices, sensors, readings, alerts, maintenance
HR	9	Employees, departments, compensation, performance
Insurance	9	Agents, policies, claims, underwriting, payments
Marketing	10	Campaigns, contacts, leads, opportunities, conversions
Education	9	Students, courses, enrollments, grades, financial aid
Real Estate	9	Agents, listings, offers, transactions, inspections
Manufacturing	9	Production lines, work orders, quality control, equipment
Telecom	9	Subscribers, service lines, usage records, billing, churn

Each domain ships with calibrated distribution profiles based on real-world data (see METHODOLOGY.md).

---

Retail Domain

The built-in RetailDomain generates a fully normalized retail schema:

Table	Small scale	Description
customer	1,000	Individual customers with loyalty tiers
address	1,500	Shipping/billing addresses with real US lat/lng
product_category	50	3-level hierarchy (dept → category → subcategory)
product	500	SKUs with correlated cost/price
store	150	Physical and online stores
promotion	200	Discount campaigns
order	5,000	Order headers with Pareto customer distribution
order_line	~12,500	Line items with discount_percent
return	~850	Returns with dates derived from order dates

Scale presets: small, medium (50K customers), large (500K), xlarge (5M)

---

Healthcare Domain

The HealthcareDomain models clinical encounters, claims, and medications:

Table	Small scale	Description
provider	200	Physicians, NPs, PAs with credentials
facility	50	Hospitals, clinics, urgent care centers
patient	1,000	Patient demographics and insurance
encounter	5,000	Office visits, ED, inpatient, telehealth
diagnosis	~9,000	ICD-10 codes linked to encounters
procedure	~6,000	CPT procedures with charges
medication	~4,500	Prescriptions with dosage and supply
claim	~4,750	Insurance claims with status
claim_line	~11,875	Claim line items with copays and adjustments

All distributions calibrated from CMS, CDC, AAMC, KFF, and BLS data — see METHODOLOGY.md.

What makes it realistic

• Pareto orders — 20% of customers place 80% of orders (max_per_parent=50 hard cap)
• Seasonal patterns — November/December peaks, Friday/Saturday peaks, bimodal hour distribution
• Real addresses — 40,977 US ZIP codes from GeoNames (CC-BY-4.0): city, state, ZIP, lat, lng. Works directly in Power BI map visuals.
• Correlated cost/price — product cost is always 30–70% of unit price
• Proper hierarchy — product categories form a real 3-level tree
• Business rules enforced — return dates always after order dates, order dates after signup dates

Address data for Power BI

addr = result["address"]
print(addr[["city", "state", "zip_code", "lat", "lng"]].head())
#            city state zip_code        lat         lng
# 0        Reform    AL    35481  33.314928  -88.042923
# 1       Chinook    MT    59523  48.487741 -109.261678

Drop the lat/lng columns directly into a Power BI map visual — no geocoding required.

---

Generation Strategies

Spindle supports 20 column-level strategies:

Strategy	Description
sequence	Auto-incrementing integer PKs
uuid	UUID v4 alternative PKs
faker	Faker library providers (names, emails, etc.)
weighted_enum	Weighted random selection from a set of values
distribution	Statistical distributions: uniform, normal, log_normal, pareto, zipf, geometric, bernoulli, bimodal
temporal	Time-aware dates: uniform or seasonal with day/month/hour profiles
formula	Computed from other columns: quantity * unit_price * (1 - discount_percent / 100)
derived	Derived from another column with a transformation: return_date = order_date + N days
correlated	Mathematically related to another column: cost = unit_price * 0.30–0.70
conditional	Conditional on another column's value
lifecycle	Phase-based status values (introduced / active / discontinued)
foreign_key	FK references with uniform, Pareto, or Zipf distribution
lookup	Copy value from parent table via FK
reference_data	Pick from bundled JSON datasets
pattern	Formatted strings: Store #{seq:4}
computed	Aggregated from child table (e.g., order_total = sum of line_totals)
self_referencing	FK to same table for hierarchy columns
self_ref_field	Read level info stashed by self_referencing
record_sample	Sample complete records from a reference dataset (anchor)
record_field	Read a field from a previously sampled record (correlated derived columns)

---

Distribution Profiles

Every domain ships with a default profile calibrated from real-world data. You can override any distribution weight:

# Override specific distributions
domain = RetailDomain(overrides={
    "customer.loyalty_tier": {"Basic": 0.40, "Silver": 0.30, "Gold": 0.20, "Platinum": 0.10},
    "order.status": {"completed": 0.85, "shipped": 0.05, "processing": 0.02, "cancelled": 0.03, "returned": 0.05},
})

# Use a named profile
domain = HealthcareDomain(profile="medicare")

# Check what's available
print(domain.available_profiles)   # ['default']
print(domain.profile_name)         # 'default'

Profile files live in domains/<name>/profiles/ and follow the same JSON schema as default.json. See METHODOLOGY.md for the full list of distribution keys and their real-world sources.

---

Custom Schemas

from sqllocks_spindle import Spindle

spindle = Spindle()
result = spindle.generate(
    schema="path/to/my_schema.spindle.json",
    scale_overrides={"customer": 10000, "order": 100000},
    seed=42
)

Schemas are defined in .spindle.json files. See PHASE-0-SPEC.md for the full schema definition format.

---

CLI

# Generate retail data at small scale
spindle generate retail --scale small --seed 42 --output ./output/

# Dry run — show what would be generated without generating
spindle generate retail --scale medium --dry-run

# Generate healthcare data as Parquet
spindle generate healthcare --scale small --format parquet --output ./data

# Stream retail orders to a file (fast mode)
spindle stream retail --table order --max-events 5000 --sink file --output events.jsonl

# Stream with real-time rate limiting and a burst window
spindle stream retail --table order --rate 100 --realtime --burst 30:60:10 --sink console

# Export to star schema (dim_* + fact_* tables as CSV)
spindle to-star retail --scale small --output ./star/

# Export to CDM folder (model.json + entity CSV files)
spindle to-cdm retail --scale small --output ./cdm/

# Describe a domain's schema and active profile
spindle describe retail

# List available domains and profiles
spindle list

# Validate a schema file
spindle validate my_schema.spindle.json

---

Development

# Create virtual environment
python3.13 -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"

# Run tests
pytest tests/ -v

# Regenerate bundled address data from GeoNames
python scripts/build_address_data.py

---

Third-Party Data

Address data (city, state, ZIP, lat, lng) is sourced from GeoNames under Creative Commons Attribution 4.0 International (CC-BY-4.0). See LICENSE-NOTICES.md.

---

License

MIT — see LICENSE

Roadmap

• Phase 0 ✅ Core engine, 21 strategies, Retail + Healthcare domains, calibrated profiles, 103 tests
• Phase 1 ✅ Fabric Lakehouse writer, CSV/Parquet/Delta/JSONL/Excel output, CLI
• Phase 2 ✅ Streaming engine — SpindleStreamer, Poisson inter-arrivals, token-bucket rate limiting, AnomalyRegistry (point/contextual/collective), Event Hub + Kafka sinks, spindle stream CLI
• Phase 3 ✅ Domain expansion — 10 new domains (12 total), 409 tests, shared reference data
• Phase 4 ✅ spindle-forge MCP server — TypeScript bridge with spindle_list_domains, spindle_describe_domain, spindle_generate
• Phase 5 ✅ PyPI packaging, GitHub Actions CI/CD, sample notebooks
• Phase 6 ✅ Star schema output, CDM folder export, fabric_demo + warehouse scale presets, spindle to-star / spindle to-cdm CLI